Bear with me here, this might be a kind've long drawn out explanation of my experience, but it might be useful or interesting to some people. I had a computer I felt could use a few upgrades, AMD 2.01ghz proc, and my brother had a PC he was discarding with a slightly better processor,AMD athlon 3500 2.21 ghz, as well as a nicer graphics card. I also managed to get a sweet new flat screen monitor out of this deal, anyway, what I wasn't aware of is that for some reason his computer would only run with ONE stick of ram. Ofcourse my current PC\mobo didn't have any qualms about filling its four slots with RAM. Anyhow, while trying to get his to run correctly we tried different combinations of ram in all the four slots, and it was tedious and unrewarding. In addition to that, it was booting strange. We figured it was a motherboard problem. So we ended up transferring the graphics card and eventually the better processor to MY computer's motherboard. The graphics card worked fine. A couple days passed and we decided to put in the processor. The processor went in, and we thought we'd somehow managed to screw something up, because the PC would not boot. The Mobo gave us error codes. C1, C3, C5 We re-examined to see if there was any physical destruction we might've caused when removing the old processor and putting in the new one, but we found none and then re-applied the processor. We got the same thing, then my brother remembered that taking out some of the chips of ram got his computer to run. We tried doing that, and suddenly the computer would boot. So it seems as though the processor itself is the thing that conflicts with the multiple sticks of memory. It had little or nothing to do with my motherboard or my brother's old motherboard. Is this a common thing with this particular kind of Processor? Did this processor just somehow.. fail in that regard? Does this happen with other ones? Or does what I'm saying sound like completely alien BS? I'm really not great with hardware, and my brother did most of the work, but he was quite mystified. I just wanna know if others have had similar problems. We're planning on putting the old 2.01 ghz processor back in when we get some more thermal paste. .5gigs of RAM hurts! By the way my mobo is an EVGA, and my brothers is an SLI.