So I got my Mac Pro about 2 months ago and recently I started having issues with Kernel Panics on a regular basis. I have 2x512mb Apple Stock memory and 2x512mb Crucial (built for MP). When I first purchased the Crucial RAM I did get failed tests when running MemtestOSX. But after a while the tests started passing so I dismissed it as a fluke or something wasnt seated right. So I kept using the memory and everything seemed to work properly for a while. Then recently whenever I try to run Compressor, Memtest, or sometimes anything memory-intensive (FCP), I get the gray curtain of doom Kernel Panic. Memtest passes with JUST the Apple RAM or JUST the Crucial RAM installed. But when both are in, I get a crash 95% of the time. Ive tried all the riser card/ram combo I can think of and nothing works. I brought it in to an Apple store, but in running their diagnostic tool they didnt find the problem (of course...). They ordered some new memory and a riser card and are going to start trouble-shooting today (which will be hard if they cant detect the problem). Did I make a mistake going with 3rd party memory? It seems like Im the only one this has happened to. Can anyone think of what the problem might be based one what Ive described? Im just worried that Apple will say its not their problem since the machine works with just their memory and they cant support 3rd party stuff. The genius I spoke with seemed very uninterested in the issue (espeically after he heard about the Crucial memory - as if to say, "Well, duh, you've got 3rd party memory, what'd you expect?"). Then Crucial could say the same thing -their memory works by itself, therefore it works period. Any comments ideas would be much appreciated.