So I bought a Mac Pro exactly one month ago. 2.66GHz with 4GB (4x1GB) Apple RAM. Everything was fine until two days ago. I noticed that OS X was now only reporting 2GB of RAM instead of 4GB. So I opened the case, and noticed a red LED on the riser board for one of the memory sticks. I isolated the problem to this one memory stick; no matter what riser board or slot I put it into, it would display a red LED. Further, upon viewing the "Power On Self-Test" Diagnostics in System Profiler, I see: Power On Self-Test: Result: Failed Failure type: Memory Memory slot: DIMM 1/DIMM Riser B So I figure I just need to get the memory stick replaced and I'd be good. So the lady on the phone says I can bring it to the "Genius" bar and they'd replace it. I go there today and after about 25 minutes of who knows what they were doing in the back room, the guy comes out and says that the riser board is bad and displaying "high temperatures" and that'd it'd need to be replaced and he'd have to order the part. He said he never saw any red LEDs and that there is no problem with the memory, despite me telling him what I said above. I also told him that I tried the first two memory sticks from the first riser board on the second riser board and it worked fine, so I doubt the riser board was bad. But he insisted. So I tell him he can order the riser board if he wants, and then he says that I actually need to leave the computer there for days until the part comes in?! For "liability" reasons. What? It's a small riser board I can install myself. Why can't they order it and I'll bring the machine back once it's in and have it replaced? I use this for business and can't go "days" without it. That's not an option. Not to mention I don't need my $3500 machine in the back room for days without knowing who's touching it or eating their lunch on it. And based on the observations above, and how other memory works fine on this riser board, I don't even think it's the problem. Is this the type of support to expect from Apple with a $3500+ computer? I had a Dell 2405FPW monitor I used for 6 months and went dead one day after a power failure. Dell overnighted me a new one and it was here at literally 9AM the next morning.. total time: 14 hours, and I sent the old one back once I received it. Right now I'm seriously considering cutting my loses on this one and just going for a Dell.. at least I know they won't dick me around like this.