You can find a list of tested and certified memory modules which have passed NVIDIA's compatibility tests on reference boards:
http://www.nvidia.com/content/nForceMemoryCompatability/lstnForceMemoryCompatibility.asp
nForce3,4,5,6,7 note: Memory controller is located within the AMD Athlon64, Opteron CPU. Please see AMD memory support document below:
AMD Athlon supported memory
http://support.amd.com/en-us/recommended/system-building/athlon
AMD Opteron supported memory
http://support.amd.com/en-us/recommended/system-building/opteron
AMD Sempron supported memory
http://support.amd.com/en-us/recommended/system-building/sempron
nForce Intel Edition supported memory
http://www.nvidia.com/object/nForce_memory_compatibility.html
nForce 7 Intel Edition supported memory
http://www.nvidia.com/content/nforce700i/nForce_Intel_Memory_List.pdf
