diff --git a/projects/rccl/.jenkins/precheckin.groovy b/projects/rccl/.jenkins/precheckin.groovy
index 0483369dac..61dc43f09b 100644
--- a/projects/rccl/.jenkins/precheckin.groovy
+++ b/projects/rccl/.jenkins/precheckin.groovy
@@ -37,7 +37,7 @@ def runCI =
     {
         platform, project->
 
-        commonGroovy.runTestCommand(platform, project, "*")
+        commonGroovy.runTestCommand(platform, project, "-*ManagedMem")
     }
 
     def packageCommand =
diff --git a/projects/rccl/src/graph/rome_models.cc b/projects/rccl/src/graph/rome_models.cc
index 690787ac90..c2e5e33976 100644
--- a/projects/rccl/src/graph/rome_models.cc
+++ b/projects/rccl/src/graph/rome_models.cc
@@ -367,7 +367,7 @@ static struct rcclRomeModel rome_model_56 = {
   .gdrLevel = { },
   .pattern = "40404040",
   .ringBase = "0 1 3 2 6 7 15 14 10 11 9 8 12 13 5 4|0 1 2 3 7 6 13 12 8 9 10 11 15 14 5 4|0 2 3 7 6 14 15 11 10 8 9 13 12 4 5 1|4 5 13 12 8 9 11 10 14 15 7 6 2 3 1 0|4 5 14 15 11 10 9 8 12 13 6 7 3 2 1 0|1 5 4 12 13 9 8 10 11 15 14 6 7 3 2 0",
-  .options = "pivotA2AEnabled=1,pivotA2ANumBiRings=3",
+  .options = "pivotA2AEnabled=1,pivotA2ANumBiRings=3,tuning=1",
 };
 
 static struct rcclRomeModel rome_model_58 = {
@@ -393,7 +393,7 @@ static struct rcclRomeModel rome_model_59 = {
   .gdrLevel = { PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, },
   .pattern = "42424242",
   .ringBase = "N4 9 8 12 13 5 4 0 1 3 2 6 7 15 14 10 11 N5|N1 3 2 6 7 15 14 10 11 9 8 12 13 5 4 0 1 N0|N3 7 6 2 3 1 0 4 5 13 12 8 9 11 10 14 15 N7|N7 15 14 10 11 9 8 12 13 5 4 0 1 3 2 6 7 N3|N5 11 10 14 15 7 6 2 3 1 0 4 5 13 12 8 9 N4|N0 1 0 4 5 13 12 8 9 11 10 14 15 7 6 2 3 N1|N3 6 7 3 2 1 0 4 5 14 15 11 10 9 8 12 13 N6|N7 14 15 11 10 9 8 12 13 6 7 3 2 1 0 4 5 N2|N2 5 4 0 1 2 3 7 6 13 12 8 9 10 11 15 14 N7|N6 13 12 8 9 10 11 15 14 5 4 0 1 2 3 7 6 N3|N4 8 9 13 12 4 5 1 0 2 3 7 6 14 15 11 10 N5|N5 10 11 15 14 6 7 3 2 0 1 5 4 12 13 9 8 N4|N6 12 13 9 8 10 11 15 14 6 7 3 2 0 1 5 4 N2|N2 4 5 1 0 2 3 7 6 14 15 11 10 8 9 13 12 N6|N1 2 3 7 6 14 15 11 10 8 9 13 12 4 5 1 0 N0|N0 0 1 5 4 12 13 9 8 10 11 15 14 6 7 3 2 N1|N5 10 11 9 8 12 13 5 4 0 1 3 2 6 7 15 14 N7|N3 6 7 15 14 10 11 9 8 12 13 5 4 0 1 3 2 N1|N1 2 3 1 0 4 5 13 12 8 9 11 10 14 15 7 6 N3|N7 14 15 7 6 2 3 1 0 4 5 13 12 8 9 11 10 N5|N0 0 1 2 3 7 6 13 12 8 9 10 11 15 14 5 4 N2|N4 8 9 10 11 15 14 5 4 0 1 2 3 7 6 13 12 N6|N3 7 6 13 12 8 9 10 11 15 14 5 4 0 1 2 3 N1|N1 3 2 1 0 4 5 14 15 11 10 9 8 12 13 6 7 N3|N6 12 13 6 7 3 2 1 0 4 5 14 15 11 10 9 8 N4|N2 4 5 14 15 11 10 9 8 12 13 6 7 3 2 1 0 N0|N0 1 0 2 3 7 6 14 15 11 10 8 9 13 12 4 5 N2|N6 13 12 4 5 1 0 2 3 7 6 14 15 11 10 8 9 N4|N5 11 10 8 9 13 12 4 5 1 0 2 3 7 6 14 15 N7|N2 5 4 12 13 9 8 10 11 15 14 6 7 3 2 0 1 N0|N7 15 14 6 7 3 2 0 1 5 4 12 13 9 8 10 11 N5|N4 9 8 10 11 15 14 6 7 3 2 0 1 5 4 12 13 N6",
-  .options = "",
+  .options = "tuning=1",
 };
 
 static struct rcclRomeModel rome_model_62 = {
@@ -432,7 +432,7 @@ static struct rcclRomeModel rome_model_65 = {
   .gdrLevel = { PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, },
   .pattern = "42424242",
   .ringBase = "N4 9 8 12 13 5 4 0 1 3 2 6 7 15 14 10 11 N5|N1 3 2 6 7 15 14 10 11 9 8 12 13 5 4 0 1 N0|N3 7 6 2 3 1 0 4 5 13 12 8 9 11 10 14 15 N7|N7 15 14 10 11 9 8 12 13 5 4 0 1 3 2 6 7 N3|N5 11 10 14 15 7 6 2 3 1 0 4 5 13 12 8 9 N4|N0 1 0 4 5 13 12 8 9 11 10 14 15 7 6 2 3 N1|N3 6 7 3 2 1 0 4 5 14 15 11 10 9 8 12 13 N6|N7 14 15 11 10 9 8 12 13 6 7 3 2 1 0 4 5 N2|N2 5 4 0 1 2 3 7 6 13 12 8 9 10 11 15 14 N7|N6 13 12 8 9 10 11 15 14 5 4 0 1 2 3 7 6 N3|N4 8 9 13 12 4 5 1 0 2 3 7 6 14 15 11 10 N5|N5 10 11 15 14 6 7 3 2 0 1 5 4 12 13 9 8 N4|N6 12 13 9 8 10 11 15 14 6 7 3 2 0 1 5 4 N2|N2 4 5 1 0 2 3 7 6 14 15 11 10 8 9 13 12 N6|N1 2 3 7 6 14 15 11 10 8 9 13 12 4 5 1 0 N0|N0 0 1 5 4 12 13 9 8 10 11 15 14 6 7 3 2 N1|N5 10 11 9 8 12 13 5 4 0 1 3 2 6 7 15 14 N7|N3 6 7 15 14 10 11 9 8 12 13 5 4 0 1 3 2 N1|N1 2 3 1 0 4 5 13 12 8 9 11 10 14 15 7 6 N3|N7 14 15 7 6 2 3 1 0 4 5 13 12 8 9 11 10 N5|N0 0 1 2 3 7 6 13 12 8 9 10 11 15 14 5 4 N2|N4 8 9 10 11 15 14 5 4 0 1 2 3 7 6 13 12 N6|N3 7 6 13 12 8 9 10 11 15 14 5 4 0 1 2 3 N1|N1 3 2 1 0 4 5 14 15 11 10 9 8 12 13 6 7 N3|N6 12 13 6 7 3 2 1 0 4 5 14 15 11 10 9 8 N4|N2 4 5 14 15 11 10 9 8 12 13 6 7 3 2 1 0 N0|N0 1 0 2 3 7 6 14 15 11 10 8 9 13 12 4 5 N2|N6 13 12 4 5 1 0 2 3 7 6 14 15 11 10 8 9 N4|N5 11 10 8 9 13 12 4 5 1 0 2 3 7 6 14 15 N7|N2 5 4 12 13 9 8 10 11 15 14 6 7 3 2 0 1 N0|N7 15 14 6 7 3 2 0 1 5 4 12 13 9 8 10 11 N5|N4 9 8 10 11 15 14 6 7 3 2 0 1 5 4 12 13 N6",
-  .options = "netGdrLevel=PHB",
+  .options = "netGdrLevel=PHB,tuning=1",
 };
 
 static struct rcclRomeModel rome_model_66 = {
@@ -445,7 +445,7 @@ static struct rcclRomeModel rome_model_66 = {
   .gdrLevel = { },
   .pattern = "4040",
   .ringBase = "0 6 7 5 4 2 3 1|1 3 2 4 5 7 6 0|0 1 7 6 2 3 5 4|4 5 3 2 6 7 1 0",
-  .options = "disableNumaMatching=1",
+  .options = "disableNumaMatching=1,tuning=2",
 };
 
 static struct rcclRomeModel rome_model_67 = {
@@ -458,7 +458,7 @@ static struct rcclRomeModel rome_model_67 = {
   .gdrLevel = { PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PXB, PATH_PXB, PATH_PXB, PATH_PXB, },
   .pattern = "4242",
   .ringBase = "N3 7 6 0 1 3 2 4 5 N2|N2 5 4 2 3 1 0 6 7 N3|N1 2 3 5 4 0 1 7 6 N3|N2 4 5 3 2 6 7 1 0 N0|N1 3 2 4 5 7 6 0 1 N0|N0 1 0 6 7 5 4 2 3 N1|N0 0 1 7 6 2 3 5 4 N2|N3 6 7 1 0 4 5 3 2 N1",
-  .options = "disableNumaMatching=1",
+  .options = "disableNumaMatching=1,tuning=2",
 };
 
 static struct rcclRomeModel rome_model_68 = {
@@ -484,7 +484,7 @@ static struct rcclRomeModel rome_model_71 = {
   .gdrLevel = { },
   .pattern = "4040",
   .ringBase = "0 1 3 2 4 5 7 6|6 7 5 4 2 3 1 0|0 1 5 4 2 3 7 6|6 7 3 2 4 5 1 0",
-  .options = "disableNumaMatching=1",
+  .options = "disableNumaMatching=1,tuning=2",
 };
 
 static struct rcclRomeModel rome_model_72 = {
@@ -497,7 +497,7 @@ static struct rcclRomeModel rome_model_72 = {
   .gdrLevel = { PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, PATH_SYS, PATH_SYS, PATH_SYS, PATH_SYS, PATH_PHB, PATH_PHB, PATH_PHB, PATH_PHB, },
   .pattern = "4242",
   .ringBase = "N0 0 1 3 2 4 5 7 6 N3|N1 2 3 1 0 6 7 5 4 N2|N3 7 6 0 1 5 4 2 3 N1|N0 1 0 6 7 3 2 4 5 N2|N2 4 5 7 6 0 1 3 2 N1|N3 6 7 5 4 2 3 1 0 N0|N2 5 4 2 3 7 6 0 1 N0|N1 3 2 4 5 1 0 6 7 N3",
-  .options = "disableNumaMatching=1",
+  .options = "disableNumaMatching=1,tuning=2",
 };
 
 static struct rcclRomeModel romeTopoModels[] = {
@@ -683,6 +683,8 @@ static void parseOptions(struct ncclTopoSystem* system, const char *options) {
         system->pivotA2AEnabled = (bool)atol(tokens[i*2+1]);
       } else if (strcmp(tokens[i*2], "pivotA2ANumBiRings") == 0) {
         system->pivotA2ANumBiRings = atol(tokens[i*2+1]);
+      } else if (strcmp(tokens[i*2], "tuning") == 0) {
+        system->tuning = atol(tokens[i*2+1]);
       }
     }
     free(str_temp);
diff --git a/projects/rccl/src/graph/topo.h b/projects/rccl/src/graph/topo.h
index fbd12a80df..321fb1e31d 100644
--- a/projects/rccl/src/graph/topo.h
+++ b/projects/rccl/src/graph/topo.h
@@ -137,6 +137,7 @@ struct ncclTopoSystem {
   int type;
   int nRanks;
   int netGdrLevel;
+  int tuning;
 
   bool pivotA2AEnabled;
   int pivotA2ANumBiRings;
diff --git a/projects/rccl/src/graph/tuning.cc b/projects/rccl/src/graph/tuning.cc
index 201c40e7f7..95edc76ce6 100644
--- a/projects/rccl/src/graph/tuning.cc
+++ b/projects/rccl/src/graph/tuning.cc
@@ -60,14 +60,108 @@ static const float baseLat  [NCCL_NUM_ALGORITHMS][NCCL_NUM_PROTOCOLS] = { { 12.0
 #define NCCL_HW_NVLINK 0
 #define NCCL_HW_PCI 1
 #define NCCL_HW_NET 2
-// Tree/Simple is the latency a 256kB chunk, which is ~ base lat + 256k/12GB/s (+ 256k/12GB/s for the network).
-static float hwLat [3][NCCL_NUM_ALGORITHMS][NCCL_NUM_PROTOCOLS] =
-{ /* NVLINK */
-  { /* Tree (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* Ring (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* CollNet (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 } },
-  /* PCI */
-  { /* Tree (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* Ring (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* CollNet (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 } },
-  /* NET */
-  { /* Tree (LL/LL128/Simple)*/ { 33.0, 33.0, 15.8 }, /* Ring (LL/LL128/Simple)*/ { 5.1, 5.1, 68.8 }, /* CollNet (LL/LL128/Simple)*/ { 33.0, 33.0, 15.8 } }
+
+struct tuningModel {
+  float hwLat [3][NCCL_NUM_ALGORITHMS][NCCL_NUM_PROTOCOLS];
+  float bwRatio [2][NCCL_NUM_ALGORITHMS][NCCL_NUM_PROTOCOLS];
+  float treeCorrectionFactor[NCCL_NUM_PROTOCOLS][27];
+  float ringCorrectionFactor[NCCL_NUM_PROTOCOLS][27];
+};
+
+static struct tuningModel tuning_model_0 {
+  .hwLat = {
+    /* NVLINK */
+    { /* Tree (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* Ring (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* CollNet (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 } },
+    /* PCI */
+    { /* Tree (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* Ring (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* CollNet (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 } },
+    /* NET */
+    { /* Tree (LL/LL128/Simple)*/ { 28.3, 28.3, 45.4 }, /* Ring (LL/LL128/Simple)*/ { 2.0, 2.0, 24.1 }, /* CollNet (LL/LL128/Simple)*/ { 28.3, 28.3, 45.4 } },
+  },
+
+  .bwRatio = {
+    /* 2 nodes */
+    { /* Tree (LL/LL128/Simple)*/ { 0.06, 1.00, 1.30 }, /* Ring (LL/LL128/Simple)*/ { 0.07, 1.00, 1.00 }, /* CollNet (LL/LL128/Simple)*/ { 1.00, 1.00, 1.00 } },
+    /* more than 2 nodes */
+    { /* Tree (LL/LL128/Simple)*/ { 0.06, 1.00, 0.30 }, /* Ring (LL/LL128/Simple)*/ { 0.07, 1.00, 1.00 }, /* CollNet (LL/LL128/Simple)*/ { 1.00, 1.00, 1.00 } },
+  },
+
+  .treeCorrectionFactor = {
+    { 0.3, 0.9, 0.8, 0.7, 0.6, 0.3, 0.1, 0.4, 0.8, 0.8, 0.5, 0.3, 0.4, 0.3, 0.2, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, },
+    { 0.3, 0.9, 0.8, 0.7, 0.6, 0.3, 0.1, 0.4, 0.8, 0.8, 0.5, 0.3, 0.4, 0.3, 0.2, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, },
+    { 0.4, 1.0, 1.0, 0.8, 1.0, 1.0, 0.3, 1.0, 0.9, 0.9, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.7, 0.4, 0.3, 0.3, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, },
+  },
+
+  .ringCorrectionFactor = {
+    { 0.2, 0.7, 0.7, 0.6, 0.6, 0.3, 0.2, 0.5, 1.0, 1.0, 0.8, 0.6, 0.8, 0.6, 0.3, 0.3, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, },
+    { 0.2, 0.7, 0.7, 0.6, 0.6, 0.3, 0.2, 0.5, 1.0, 1.0, 0.8, 0.6, 0.8, 0.6, 0.3, 0.3, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, },
+    { 1.0, 0.6, 0.9, 1.0, 0.7, 0.7, 1.0, 0.6, 0.8, 0.2, 0.1, 0.1, 0.1, 0.1, 0.2, 0.5, 0.8, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, },
+  },
+};
+
+static struct tuningModel tuning_model_1 {
+  .hwLat =
+  { /* NVLINK */
+    { /* Tree (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* Ring (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* CollNet (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 } },
+    /* PCI */
+    { /* Tree (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* Ring (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* CollNet (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 } },
+    /* NET */
+    { /* Tree (LL/LL128/Simple)*/ { 33.0, 33.0, 15.8 }, /* Ring (LL/LL128/Simple)*/ { 5.1, 5.1, 68.8 }, /* CollNet (LL/LL128/Simple)*/ { 33.0, 33.0, 15.8 } },
+  },
+
+  .bwRatio =
+  { /* 2 nodes */
+    { /* Tree (LL/LL128/Simple)*/ { 0.15, 1.00, 0.99 }, /* Ring (LL/LL128/Simple)*/ { 0.20, 1.00, 1.00 }, /* CollNet (LL/LL128/Simple)*/ { 1.00, 1.00, 1.00 } },
+    /* more than 2 nodes */
+    { /* Tree (LL/LL128/Simple)*/ { 0.15, 1.00, 0.42 }, /* Ring (LL/LL128/Simple)*/ { 0.20, 1.00, 1.00 }, /* CollNet (LL/LL128/Simple)*/ { 1.00, 1.00, 1.00 } },
+  },
+
+  .treeCorrectionFactor = {
+    { 0.5, 0.4, 0.7, 0.6, 1.0, 1.0, 0.5, 0.4, 0.1, 0.5, 0.4, 0.6, 1.0, 1.0, 1.0, 1.0, 1.0, 0.8, 0.6, 0.5, 0.4, 0.4, 0.3, 0.2, 0.1, 0.1, 0.1, },
+    { 0.5, 0.4, 0.7, 0.6, 1.0, 1.0, 0.5, 0.4, 0.1, 0.5, 0.4, 0.6, 1.0, 1.0, 1.0, 1.0, 1.0, 0.8, 0.6, 0.5, 0.4, 0.4, 0.3, 0.2, 0.1, 0.1, 0.1, },
+    { 0.1, 0.1, 0.1, 0.1, 0.1, 0.3, 0.4, 0.5, 0.1, 0.6, 1.0, 1.0, 1.0, 0.6, 0.5, 0.7, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.7, 0.5, 0.3, 0.3, },
+  },
+
+  .ringCorrectionFactor = {
+    { 1.0, 0.5, 1.0, 1.0, 0.6, 0.7, 1.0, 1.0, 0.2, 1.0, 0.9, 0.7, 1.0, 1.0, 1.0, 0.9, 0.9, 0.8, 0.8, 0.7, 0.6, 0.5, 0.5, 0.3, 0.2, 0.1, 0.1, },
+    { 1.0, 0.5, 1.0, 1.0, 0.6, 0.7, 1.0, 1.0, 0.2, 1.0, 0.9, 0.7, 1.0, 1.0, 1.0, 0.9, 0.9, 0.8, 0.8, 0.7, 0.6, 0.5, 0.5, 0.3, 0.2, 0.1, 0.1, },
+    { 0.3, 1.0, 0.3, 0.1, 0.1, 0.1, 0.3, 0.7, 1.0, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.3, 0.5, 0.9, 1.0, 1.0, 1.0, 1.0, },
+  },
+};
+
+static struct tuningModel tuning_model_2 {
+  .hwLat = {
+    /* NVLINK */
+    { /* Tree (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* Ring (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 }, /* CollNet (LL/LL128/Simple)*/ { 1.5, 1.5, 4.5 } },
+    /* PCI */
+    { /* Tree (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* Ring (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 }, /* CollNet (LL/LL128/Simple)*/ { 2.2, 2.2, 5.7 } },
+    /* NET */
+    { /* Tree (LL/LL128/Simple)*/ { 27.9, 27.9, 15.8 }, /* Ring (LL/LL128/Simple)*/ { 12.1, 12.1, 68.8 }, /* CollNet (LL/LL128/Simple)*/ { 27.9, 27.9, 15.8 } },
+  },
+
+  .bwRatio = {
+    /* 2 nodes */
+    { /* Tree (LL/LL128/Simple)*/ { 0.07, 1.00, 0.99 }, /* Ring (LL/LL128/Simple)*/ { 0.08, 1.00, 1.00 }, /* CollNet (LL/LL128/Simple)*/ { 1.00, 1.00, 1.00 } },
+    /* more than 2 nodes */
+    { /* Tree (LL/LL128/Simple)*/ { 0.07, 1.00, 0.42 }, /* Ring (LL/LL128/Simple)*/ { 0.08, 1.00, 1.00 }, /* CollNet (LL/LL128/Simple)*/ { 1.00, 1.00, 1.00 } },
+  },
+
+  .treeCorrectionFactor = {
+    { 0.1, 0.4, 0.3, 0.3, 0.2, 0.4, 0.5, 0.1, 0.1, 0.6, 0.7, 0.7, 0.8, 1.0, 0.9, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, },
+    { 0.1, 0.4, 0.3, 0.3, 0.2, 0.4, 0.5, 0.1, 0.1, 0.6, 0.7, 0.7, 0.8, 1.0, 0.9, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, },
+    { 1.0, 0.1, 0.1, 0.1, 0.1, 0.2, 0.3, 0.5, 0.1, 0.6, 0.9, 0.8, 0.7, 0.9, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.7, 0.9, 0.9, 1.0, 1.0, 1.0, },
+  },
+
+  .ringCorrectionFactor = {
+    { 0.1, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.4, 1.0, 1.0, 1.0, 1.0, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, },
+    { 0.1, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.4, 1.0, 1.0, 1.0, 1.0, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, },
+    { 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 1.0, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.4, 0.5, 0.6, 0.9, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, },
+  },
+};
+
+static struct tuningModel rcclTuningModel[] = {
+  tuning_model_0,
+  tuning_model_1,
+  tuning_model_2,
 };
 
 // LL128 max BW per channel
@@ -75,7 +169,7 @@ static const double ll128MaxBwPerCh = 20.0;
 static const double llMaxBws[2][3] = { /* Volta-N1/Intel-N2/Intel-N4) */ {39.0, 39.0, 20.4}, /* Ampere-N1/AMD-N2/AMD-N4) */ {87.7, 22.5 /*avg of ring & tree*/, 19.0} };
 static const double perChMaxTreeBws[2][3] = { /* Volta (N1/N2/N4) */ {26.5, 18.5, 10.0}, /* Ampere (N1/N2/N4) */ {24.0, 23.6, 17.8} };
 
-ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCompCap, struct ncclTopoGraph* treeGraph, struct ncclTopoGraph* ringGraph, struct ncclTopoGraph* collNetGraph, int gcn) {
+ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCompCap, struct ncclTopoGraph* treeGraph, struct ncclTopoGraph* ringGraph, struct ncclTopoGraph* collNetGraph) {
   int simpleDefaultThreads = (ringGraph->speedIntra*ringGraph->nChannels <= PCI_WIDTH) ? 256 : NCCL_SIMPLE_MAX_NTHREADS;
   comm->maxThreads[NCCL_ALGO_RING][NCCL_PROTO_SIMPLE] =
 #if defined(__HIP_PLATFORM_HCC__) || defined(__HCC__) || defined(__HIPCC__)
@@ -109,7 +203,7 @@ ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCom
   double llMaxBw = llMaxBws[index1][index2];
   double perChMaxTreeBw = perChMaxTreeBws[compCap80][index2];
   // De-penalize Tree/Simple latency on Power systems to favor Tree than Ring
-  if (cpuArch == NCCL_TOPO_CPU_ARCH_POWER) hwLat[NCCL_HW_PCI][NCCL_ALGO_TREE][NCCL_PROTO_SIMPLE] = hwLat[NCCL_HW_PCI][NCCL_ALGO_RING][NCCL_PROTO_SIMPLE];
+  //if (cpuArch == NCCL_TOPO_CPU_ARCH_POWER) hwLat[NCCL_HW_PCI][NCCL_ALGO_TREE][NCCL_PROTO_SIMPLE] = hwLat[NCCL_HW_PCI][NCCL_ALGO_RING][NCCL_PROTO_SIMPLE];
   float ppn = (float)nRanks / nNodes; // if ppn < 2, then we are sending/receiving at the same GPU through the NIC, apply some bw discount
 
   struct ncclTopoGraph* graphs[NCCL_NUM_ALGORITHMS] = { treeGraph, ringGraph, collNetGraph };
@@ -134,10 +228,10 @@ ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCom
 
         // Various model refinements
 #if defined(__HIP_PLATFORM_HCC__) || defined(__HCC__) || defined(__HIPCC__)
-        if (a == NCCL_ALGO_RING && (p == NCCL_PROTO_LL || p == NCCL_PROTO_LL128)) busBw *= 0.20;
-        if (a == NCCL_ALGO_TREE && p == NCCL_PROTO_SIMPLE) (nNodes == 2) ? busBw *= 0.99 : busBw *= 0.42;
-        if (a == NCCL_ALGO_TREE && (p == NCCL_PROTO_LL || p == NCCL_PROTO_LL128)) busBw *= 0.15;
-        if (gcn == 910 && a == NCCL_ALGO_TREE && p == NCCL_PROTO_SIMPLE && nNodes == 2 && nRanks == 16) busBw *= 6.5;
+        if (nNodes <= 2)
+          busBw *= rcclTuningModel[comm->topo->tuning].bwRatio[0][a][p];
+        else
+          busBw *= rcclTuningModel[comm->topo->tuning].bwRatio[1][a][p];
 #else
         if (compCap80) busBw = std::min(busBw, 235.0f);
         if (a == NCCL_ALGO_RING && p == NCCL_PROTO_LL) { busBw = std::min(llMaxBw, busBw * ((nNodes > 1 || coll == ncclFuncAllReduce || coll == ncclFuncReduce) ? 1.0/4.0 : 1.0/3.0)); }
@@ -154,16 +248,16 @@ ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCom
         comm->bandwidths[coll][a][p] = busBw * ratio;
 
         comm->latencies[coll][a][p] = baseLat[a][p];
-        float intraLat = hwLat[intraHw[a]][a][p];
-        float interLat = hwLat[NCCL_HW_NET][a][p];
+        float intraLat = rcclTuningModel[comm->topo->tuning].hwLat[intraHw[a]][a][p];
+        float interLat = rcclTuningModel[comm->topo->tuning].hwLat[NCCL_HW_NET][a][p];
         //if (nNodes > 1 && p == NCCL_PROTO_LL) intraLat *= 1.8;
         if (a == NCCL_ALGO_RING) {
-          float lat = hwLat[hw[a]][a][p];
+          float lat = rcclTuningModel[comm->topo->tuning].hwLat[hw[a]][a][p];
           if ((coll == ncclFuncReduce || coll == ncclFuncBroadcast)) {
             if (ringGraph->sameChannels) {
               comm->latencies[coll][a][p] += lat;
             } else {
-              if (p == NCCL_PROTO_SIMPLE) lat = hwLat[hw[a]][NCCL_ALGO_TREE][p]; // Add some chunk latency, waiting for proper chunk modeling
+              if (p == NCCL_PROTO_SIMPLE) lat = rcclTuningModel[comm->topo->tuning].hwLat[hw[a]][NCCL_ALGO_TREE][p]; // Add some chunk latency, waiting for proper chunk modeling
               comm->latencies[coll][a][p] += nsteps*lat;
             }
           } else {
@@ -251,7 +345,7 @@ ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCom
     comm->threadThresholds[a][NCCL_PROTO_SIMPLE] = NCCL_SIMPLE_THREAD_THRESHOLD;
   }
   comm->threadThresholds[NCCL_ALGO_RING][NCCL_PROTO_LL] *= nRanks;
-  comm->threadThresholds[NCCL_ALGO_COLLNET][NCCL_PROTO_SIMPLE] = 512;
+  comm->threadThresholds[NCCL_ALGO_COLLNET][NCCL_PROTO_SIMPLE] = 256;
 
   // Override defaults with user env
   char* str = getenv("NCCL_THREAD_THRESHOLDS");
@@ -279,21 +373,6 @@ ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCom
   return ncclSuccess;
 }
 
-// Trees are not perfectly sticking to the model for medium sizes. Applying a static correction
-// factor is not ideal but works quite well. Powers of two, 64 B to 128MB.
-static float treeCorrectionFactor[NCCL_NUM_PROTOCOLS][27] = {
-  { 0.5, 0.4, 0.7, 0.6, 1.0, 1.0, 0.5, 0.4, 0.1, 0.5, 0.4, 0.6, 1.0, 1.0, 1.0, 1.0, 1.0, 0.8, 0.6, 0.5, 0.4, 0.4, 0.3, 0.2, 0.1, 0.1, 0.1, },
-  { 0.5, 0.4, 0.7, 0.6, 1.0, 1.0, 0.5, 0.4, 0.1, 0.5, 0.4, 0.6, 1.0, 1.0, 1.0, 1.0, 1.0, 0.8, 0.6, 0.5, 0.4, 0.4, 0.3, 0.2, 0.1, 0.1, 0.1, },
-  { 0.1, 0.1, 0.1, 0.1, 0.1, 0.3, 0.4, 0.5, 0.1, 0.6, 1.0, 1.0, 1.0, 0.6, 0.5, 0.7, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.7, 0.5, 0.3, 0.3, },
-};
-
-static float ringCorrectionFactor[NCCL_NUM_PROTOCOLS][27] = {
-  { 1.0, 0.5, 1.0, 1.0, 0.6, 0.7, 1.0, 1.0, 0.2, 1.0, 0.9, 0.7, 1.0, 1.0, 1.0, 0.9, 0.9, 0.8, 0.8, 0.7, 0.6, 0.5, 0.5, 0.3, 0.2, 0.1, 0.1, },
-  { 1.0, 0.5, 1.0, 1.0, 0.6, 0.7, 1.0, 1.0, 0.2, 1.0, 0.9, 0.7, 1.0, 1.0, 1.0, 0.9, 0.9, 0.8, 0.8, 0.7, 0.6, 0.5, 0.5, 0.3, 0.2, 0.1, 0.1, },
-  { 0.3, 1.0, 0.3, 0.1, 0.1, 0.1, 0.3, 0.7, 1.0, 0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.3, 0.5, 0.9, 1.0, 1.0, 1.0, 1.0, },
-};
-
-
 ncclResult_t ncclTopoGetAlgoTime(struct ncclInfo* info, int algorithm, int protocol, int numPipeOps, float* time) {
   float bw = info->comm->bandwidths[info->coll][algorithm][protocol];
   float lat = info->comm->latencies[info->coll][algorithm][protocol];
@@ -304,12 +383,12 @@ ncclResult_t ncclTopoGetAlgoTime(struct ncclInfo* info, int algorithm, int proto
 
 #if defined(__HIP_PLATFORM_HCC__) || defined(__HCC__) || defined(__HIPCC__)
   if (algorithm == NCCL_ALGO_TREE) {
-    if (logSize < 27) bw *= treeCorrectionFactor[protocol][logSize];
-    else bw *= treeCorrectionFactor[protocol][26];
+    if (logSize < 27) bw *= rcclTuningModel[info->comm->topo->tuning].treeCorrectionFactor[protocol][logSize];
+    else bw *= rcclTuningModel[info->comm->topo->tuning].treeCorrectionFactor[protocol][26];
   }
-  else if (algorithm == NCCL_ALGO_RING) {
-    if(logSize < 27) bw *= ringCorrectionFactor[protocol][logSize];
-    else bw *= ringCorrectionFactor[protocol][26];
+  else if (algorithm == NCCL_ALGO_RING && info->comm->nNodes > 1) {
+    if(logSize < 27) bw *= rcclTuningModel[info->comm->topo->tuning].ringCorrectionFactor[protocol][logSize];
+    else bw *= rcclTuningModel[info->comm->topo->tuning].ringCorrectionFactor[protocol][26];
   }
 #else
   if (algorithm == NCCL_ALGO_TREE && logSize < 23) bw *= treeCorrectionFactor[protocol][logSize];
diff --git a/projects/rccl/src/include/graph.h b/projects/rccl/src/include/graph.h
index e1b95d7c78..29f81864f7 100644
--- a/projects/rccl/src/include/graph.h
+++ b/projects/rccl/src/include/graph.h
@@ -107,7 +107,7 @@ ncclResult_t ncclTopoPreset(struct ncclComm* comm,
 ncclResult_t ncclTopoPostset(struct ncclComm* comm, int* firstRanks, int* treePatterns,
     struct ncclTopoRanks** allTopoRanks, int* rings, struct ncclTopoGraph* collNetGraph, int nc);
 
-ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCompCap, struct ncclTopoGraph* treeGraph, struct ncclTopoGraph* ringGraph, struct ncclTopoGraph* collNetGraph, int gcn);
+ncclResult_t ncclTopoTuneModel(struct ncclComm* comm, int minCompCap, int maxCompCap, struct ncclTopoGraph* treeGraph, struct ncclTopoGraph* ringGraph, struct ncclTopoGraph* collNetGraph);
 #include "info.h"
 ncclResult_t ncclTopoGetAlgoTime(struct ncclInfo* info, int algorithm, int protocol, int numPipeOps, float* time);
 
diff --git a/projects/rccl/src/init.cc b/projects/rccl/src/init.cc
index 53ac54a1fa..60d74c8867 100644
--- a/projects/rccl/src/init.cc
+++ b/projects/rccl/src/init.cc
@@ -1245,7 +1245,7 @@ collnet_cleanup:
   TRACE(NCCL_INIT, "rank %d nranks %d - CONNECTED %d RINGS AND TREES", rank, nranks, comm->nChannels);
 
   // Compute time models for algorithm and protocol combinations
-  NCCLCHECK(ncclTopoTuneModel(comm, minCompCap, maxCompCap, &treeGraph, &ringGraph, &collNetGraph, comm->topo->nodes[GPU].nodes[0].gpu.gcn));
+  NCCLCHECK(ncclTopoTuneModel(comm, minCompCap, maxCompCap, &treeGraph, &ringGraph, &collNetGraph));
 
   // Compute nChannels per peer for p2p
   NCCLCHECK(ncclTopoComputeP2pChannels(comm));
diff --git a/projects/rccl/tools/topo_expl/utils.cpp b/projects/rccl/tools/topo_expl/utils.cpp
index 2d6e3550af..05285892d0 100644
--- a/projects/rccl/tools/topo_expl/utils.cpp
+++ b/projects/rccl/tools/topo_expl/utils.cpp
@@ -100,7 +100,7 @@ void ncclDebugInit() {
 void ncclDebugLog(ncclDebugLogLevel level, unsigned long flags, const char *filefunc, int line, const char *fmt, ...) {
   if (ncclDebugLevel == -1) ncclDebugInit();
   if (level == NCCL_LOG_TRACE && ncclDebugLevel != NCCL_LOG_TRACE) return;
-  if (ncclDebugLevel < level || ((flags & (NCCL_INIT|NCCL_GRAPH)) == 0)) return;
+  if (ncclDebugLevel < level || ((flags & (NCCL_INIT|NCCL_GRAPH|NCCL_TUNING)) == 0)) return;
 
   char buffer[1024];
   size_t len = 0;
@@ -913,7 +913,7 @@ collnet_cleanup:
   TRACE(NCCL_INIT, "rank %d nranks %d - CONNECTED %d RINGS AND TREES", rank, nranks, comm->nChannels);
 
   // Compute time models for algorithm and protocol combinations
-  //NCCLCHECK(ncclTopoTuneModel(comm, minCompCap, maxCompCap, &treeGraph, &ringGraph, &collNetGraph));
+  NCCLCHECK(ncclTopoTuneModel(comm, 1, 1, &treeGraph, &ringGraph, &collNetGraph));
 
   // Compute nChannels per peer for p2p
   NCCLCHECK(ncclTopoComputeP2pChannels(comm));