I've been trying to troubleshoot a fix for my MP for nearly 2 months with an applecare rep. My CPU fans run up to 400rpm higher than is normal. I tried the normal things (smc reset, etc) but that didn't help. The fans' minimum speed seemed to be stuck and it would never rev down, even when the cpu temps were at room temp (after I let it sit off for a while). This happened in Windows, Leopard/SL, the Leopard boot disk, and when booted off an external drive. I contacted applecare and went through some troubleshooting with him including capturing data from the computer, etc. No luck. He suggested that I bring it to an Apple store to let them run the full diagnostics. I did that and they kept it for a few days and said that it passed all of the diagnostics and there was nothing wrong with it. False (as I will soon explain to you). The applecare rep had a local tech service send someone out to my house with parts that would likely fix the issue. The tech first ran a diagnostic which showed that something failed (I believe the heatsink/fan assembly because it couldn't rev down to the minimum speeds). This test took < 20 minutes to show a failure so I'm not sure what the apple store did with my machine over the weekend, but they didn't do much! The tech then opened the case to replace some parts, only to find that the processor cage had never been reattached when disassembled from the Apple store! So not only had the genius not properly diagnosed it, he didn't put it back together properly. Anywho, the tech replaced some parts (I believe it was the processor board, processors, heatsinks/fans, and the case intake/exhaust fans) but that didn't fix the problem. The tech came out again later in the month with a new back plane board (where I believe the SMC resides) and I was SURE that it would fix it. What else was there besides the PSU?! Annnnnnnnnnd it didn't. My applecare rep contacted me when I alerted him that it wasn't fixed. He offered to replace the machine. I agreed that this seemed to be the best course of action. Between replacing so many expensive parts and sending a tech on two house calls, I'm sure they had already spent a significant amount of money on trying to fix my machine. The applecare rep informed me that, for my "hassle" and the time it took to unsuccessfully troubleshoot the problem, Apple would hand me upgraded processors for free!!! They're currently building a machine spec'd the same as I bought it in March 09 with the exception of dual quad core 2.66 GHz processors!!!! That would have been a $1400 upgrade had I chosen that at purchase. Needless to say, I'm quite ecstatic with the resolution. For a relatively minor problem (some would even contend that it's not a problem since it keeps your processors cooler, etc.), they really made sure that I was happy with the result. I'm sorry for the exceedingly long story but I wanted to relay my good experience with Apple's customer service. There are plenty of "I got screwed by Apple" posts around so I wanted to take the time to show the other side of the coin.