diff --git a/configs/ruby/MESI_CMP_directory.py b/configs/ruby/MESI_CMP_directory.py
index 4128f87ad7..e263b4e5a1 100644
--- a/configs/ruby/MESI_CMP_directory.py
+++ b/configs/ruby/MESI_CMP_directory.py
@@ -142,6 +142,7 @@ def create_system(options, system, piobus, dma_ports, ruby_system):
 
     phys_mem_size = sum(map(lambda mem: mem.range.size(),
                             system.memories.unproxy(system)))
+    assert(phys_mem_size % options.num_dirs == 0)
     mem_module_size = phys_mem_size / options.num_dirs
 
     # Run each of the ruby memory controllers at a ratio of the frequency of
diff --git a/configs/ruby/MI_example.py b/configs/ruby/MI_example.py
index 6bbd35ea78..896a01a61e 100644
--- a/configs/ruby/MI_example.py
+++ b/configs/ruby/MI_example.py
@@ -107,6 +107,7 @@ def create_system(options, system, piobus, dma_ports, ruby_system):
 
     phys_mem_size = sum(map(lambda mem: mem.range.size(),
                             system.memories.unproxy(system)))
+    assert(phys_mem_size % options.num_dirs == 0)
     mem_module_size = phys_mem_size / options.num_dirs
 
     # Run each of the ruby memory controllers at a ratio of the frequency of
diff --git a/configs/ruby/MOESI_CMP_directory.py b/configs/ruby/MOESI_CMP_directory.py
index 81d04914c6..bc1f7d6410 100644
--- a/configs/ruby/MOESI_CMP_directory.py
+++ b/configs/ruby/MOESI_CMP_directory.py
@@ -137,6 +137,7 @@ def create_system(options, system, piobus, dma_ports, ruby_system):
 
     phys_mem_size = sum(map(lambda mem: mem.range.size(),
                             system.memories.unproxy(system)))
+    assert(phys_mem_size % options.num_dirs == 0)
     mem_module_size = phys_mem_size / options.num_dirs
 
     # Run each of the ruby memory controllers at a ratio of the frequency of
diff --git a/configs/ruby/MOESI_CMP_token.py b/configs/ruby/MOESI_CMP_token.py
index 9c2598a1df..4ede788a82 100644
--- a/configs/ruby/MOESI_CMP_token.py
+++ b/configs/ruby/MOESI_CMP_token.py
@@ -158,6 +158,7 @@ def create_system(options, system, piobus, dma_ports, ruby_system):
 
     phys_mem_size = sum(map(lambda mem: mem.range.size(),
                             system.memories.unproxy(system)))
+    assert(phys_mem_size % options.num_dirs == 0)
     mem_module_size = phys_mem_size / options.num_dirs
 
     # Run each of the ruby memory controllers at a ratio of the frequency of
diff --git a/configs/ruby/MOESI_hammer.py b/configs/ruby/MOESI_hammer.py
index 11ea579ea5..da8b004ee3 100644
--- a/configs/ruby/MOESI_hammer.py
+++ b/configs/ruby/MOESI_hammer.py
@@ -133,6 +133,7 @@ def create_system(options, system, piobus, dma_ports, ruby_system):
 
     phys_mem_size = sum(map(lambda mem: mem.range.size(),
                             system.memories.unproxy(system)))
+    assert(phys_mem_size % options.num_dirs == 0)
     mem_module_size = phys_mem_size / options.num_dirs
 
     #
diff --git a/configs/ruby/Network_test.py b/configs/ruby/Network_test.py
index c4df4dddbd..d7b04cd313 100644
--- a/configs/ruby/Network_test.py
+++ b/configs/ruby/Network_test.py
@@ -105,6 +105,7 @@ def create_system(options, system, piobus, dma_ports, ruby_system):
 
     phys_mem_size = sum(map(lambda mem: mem.range.size(),
                             system.memories.unproxy(system)))
+    assert(phys_mem_size % options.num_dirs == 0)
     mem_module_size = phys_mem_size / options.num_dirs
 
     # Run each of the ruby memory controllers at a ratio of the frequency of