Mac Pro RAM Woes

You may remember how excited I was about a month ago when I got the 2GB RAM upgrade from Crucial for my Mac Pro. Well, about two weeks ago I happened to notice in Activity Monitor that I only had 3GB of RAM. That wasn’t right; I had 4GB. I started testing, and discovered a problem with the RAM. System Profiler was reporting 6 512MB sticks of RAM, instead of 4 512MB and 2 1GB sticks. I tried moving the sticks around to various banks, but never got it to see more than 3GB. Also, there are four LED’s on each of the risers that correspond to the four RAM banks. When you boot the system, these lights come on for about 2 seconds, then go out. There was one Crucial stick whose LED stayed on. No matter which bank I put that stick in, its light stayed on.

Saddened by this, I called Crucial. I spent just a few minutes on the phone with them before they agreed that there was clearly a problem, and that they would replace them. They have excellent customer and technical support. I shipped the two sticks back to them and waited.

Two days ago UPS arrived with my replacement sticks. I shut down my Mac and put the two new sticks in banks 3 and 4 of riser A, leaving the 512MB sticks in banks 1 and 2 of risers A and B, and booted. I logged-in, brought up Activity Monitor, only to see 3GB reported. System Profiler says 6 512MB sticks, just like before. The new RAM is doing exactly what the first set of RAM did. I tried every combination of placement of the sticks I could think of, including removing ALL the Apple RAM, and just putting the Crucial sticks into banks 1 and 2 of riser A. In that case, the Mac only saw 1G of RAM.

So it was back to Crucial tech support. They agreed it sounded like a bad stick (again) and are going to replace them again. I just shipped back the two latest sticks, and am once again waiting on a shipment from Crucial. I hope this one works. If it doesn’t, I’m just going to pony up the 2x extra and buy direct from Apple.

The Crucial guy said it was “hard to believe” that I got two bad sticks in a row, and I agree. But what else could it be? If I only had two banks for RAM in the computer, then you could blame it on the computer itself. But I’ve got eight banks to play with, and have tried them all. I don’t think it’s a problem with the Mac itself. I could be wrong, but I don’t think so.