diff --git a/examples/portable/aobench/Makefile_ptx b/examples/portable/aobench/Makefile_ptx
index ffc5e088..6cc1a378 100644
--- a/examples/portable/aobench/Makefile_ptx
+++ b/examples/portable/aobench/Makefile_ptx
@@ -2,10 +2,15 @@ PROG=ao
 ISPC_SRC=ao.ispc
 CU_SRC=ao.cu
 CXX_SRC=ao.cpp 
-PTXCC_REGMAX=64
-NVARCH=sm_35
+
+#K80
 #PTXCC_REGMAX=128
 #NVARCH=sm_37
+
+#K20/K40 
+PTXCC_REGMAX=64
+NVARCH=sm_35
+
 #ISPC_FLAGS= --opt=disable-uniform-control-flow
 
 #LLVM_GPU=1
diff --git a/examples/portable/deferred/Makefile_ptx b/examples/portable/deferred/Makefile_ptx
index 99f5bc0b..9052db75 100644
--- a/examples/portable/deferred/Makefile_ptx
+++ b/examples/portable/deferred/Makefile_ptx
@@ -2,6 +2,12 @@ PROG=deferred_shading
 ISPC_SRC=kernels.ispc
 CU_SRC=kernels.cu
 CXX_SRC=common.cpp  main.cpp
+
+#K80
+#PTXCC_REGMAX=128
+#NVARCH=sm_37
+
+#K20/K40 
 PTXCC_REGMAX=64
 NVARCH=sm_35
 
diff --git a/examples/portable/mergeSort/Makefile_ptx b/examples/portable/mergeSort/Makefile_ptx
index f64581e4..1b2b4917 100644
--- a/examples/portable/mergeSort/Makefile_ptx
+++ b/examples/portable/mergeSort/Makefile_ptx
@@ -2,10 +2,19 @@ PROG=mergeSort
 ISPC_SRC=mergeSort.ispc
 CU_SRC=mergeSort.cu
 CXX_SRC=mergeSort.cpp  mergeSort.cpp
-PTXCC_REGMAX=64
 #PTXCC_FLAGS= -Xptxas=-O3
 #NVCC_FLAGS=-Xptxas=-O0
 
+#K80
+#PTXCC_REGMAX=128
+#NVARCH=sm_37
+
+#K20/K40 
+PTXCC_REGMAX=64
+NVARCH=sm_35
+
+
+
 LLVM_GPU=1
 NVVM_GPU=1
 
diff --git a/examples/portable/nbody_hermite4/Makefile_ptx b/examples/portable/nbody_hermite4/Makefile_ptx
index 9a68c496..0c9300d6 100644
--- a/examples/portable/nbody_hermite4/Makefile_ptx
+++ b/examples/portable/nbody_hermite4/Makefile_ptx
@@ -2,9 +2,16 @@ PROG=hermite4
 ISPC_SRC=hermite4.ispc
 #CU_SRC=hermite4.cu
 CXX_SRC=hermite4.cpp 
-PTXCC_REGMAX=128
+
+#K80
+#PTXCC_REGMAX=128
+#NVARCH=sm_37
+
+#K20/K40 
+PTXCC_REGMAX=64
+NVARCH=sm_35
+
 #ISPC_FLAGS= --opt=disable-uniform-control-flow
-NVARCH=sm_37
 
 # LLVM_GPU=1
 NVVM_GPU=1
diff --git a/examples/portable/options/Makefile_ptx b/examples/portable/options/Makefile_ptx
index 1065eb92..b9262d2a 100644
--- a/examples/portable/options/Makefile_ptx
+++ b/examples/portable/options/Makefile_ptx
@@ -2,7 +2,16 @@ PROG=options
 ISPC_SRC=options.ispc
 CU_SRC=options.cu
 CXX_SRC=options.cpp 
+
+#K80
+#PTXCC_REGMAX=128
+#NVARCH=sm_37
+
+#K20/K40 
 PTXCC_REGMAX=128
+NVARCH=sm_35
+
+
 
 
 #LLVM_GPU=1
diff --git a/examples/portable/radixSort/Makefile_ptx b/examples/portable/radixSort/Makefile_ptx
index da7494e4..899f5b3b 100644
--- a/examples/portable/radixSort/Makefile_ptx
+++ b/examples/portable/radixSort/Makefile_ptx
@@ -4,7 +4,16 @@ ISPC_SRC=radixSort.ispc
 CU_SRC=radixSort.cu
 # NVCC_FLAGS=-Xptxas=-O1
 CXX_SRC=radixSort.cpp  radixSort.cpp
+
+#K80
+#PTXCC_REGMAX=128
+#NVARCH=sm_37
+
+#K20/K40 
 PTXCC_REGMAX=64
+NVARCH=sm_35
+
+
 
 LLVM_GPU=1
 NVVM_GPU=1
diff --git a/examples/portable/rt/Makefile_ptx b/examples/portable/rt/Makefile_ptx
index 45eae8c6..8d524bb2 100644
--- a/examples/portable/rt/Makefile_ptx
+++ b/examples/portable/rt/Makefile_ptx
@@ -2,7 +2,16 @@ PROG=rt
 ISPC_SRC=rt.ispc
 CU_SRC=rt.cu
 CXX_SRC=rt.cpp 
+
+#K20/K40 
 PTXCC_REGMAX=32
+NVARCH=sm_35
+
+#K80
+#PTXCC_REGMAX=64
+#NVARCH=sm_37
+
+
 
 #LLVM_GPU=1
 NVVM_GPU=1
diff --git a/examples/portable/volume_rendering/Makefile_ptx b/examples/portable/volume_rendering/Makefile_ptx
index 6aef695a..630a70d2 100644
--- a/examples/portable/volume_rendering/Makefile_ptx
+++ b/examples/portable/volume_rendering/Makefile_ptx
@@ -2,7 +2,16 @@ PROG=volume
 ISPC_SRC=volume.ispc
 CU_SRC=volume.cu
 CXX_SRC=volume.cpp  
+
+#K80
+#PTXCC_REGMAX=128
+#NVARCH=sm_37
+
+#K20/K40 
 PTXCC_REGMAX=64
+NVARCH=sm_35
+
+
 
 #LLVM_GPU=1
 NVVM_GPU=1