Strange Patriot RAM Problem

I originally bought one 2x1gb set of Patriot Extreme Performance RAM (5-5-5-12 2T PC2-6400) which worked flawlessly in my old system. When I built my new system, I bought another set of the same RAM to make 4gb. I know it's the same RAM because I used the link in my newegg.com order history to make sure. Now since building the new system, I get BSODs citing nvlddmkm when I play games such as WoW or AoC. After ruling out the obvious I decided to look into a memory problem.

My memory passes MemTest no matter how many passes I perform. However, today I checked my memory in CPU-Z and this is what I found:

One set of memory has part number: PDC22G6400ELK and recommends 2.0v
While the other one shows: 6400 EL Series and recommends 1.9v

Could this be causing compatibility issues? If so, does anybody know which set I should return to make sure I get a set that will play nice?

My System:
Intel E8400 @ 3.0ghz
ASUS P5N-D nForce 750i SLi
Zotac 8800gt 512mb
4gb (4x1gb) Patriot Extreme Performance RAM
Windows Vista 64 bit

Turns out that the BSOD was not memory related after all. I've pretty much been able to conclude that the problem is a bad PCI-E slot. I've been running test after test as well as gaming (for 4+ hours... horray free time!) with my video card in the other PCI-E slot and I have yet to encounter an error where as before I would get an error after about 20 minutes.

But I did run Prime95 and 3dmark06 prior to my first post. Both ran without complication.