I've recently been trying to upgrade the memory in an 838GM, and so far it's rejected all of it. On startup it will give the three beeps indicative of a memory error, and fail to POST. I have only been using PC3200 that was specifically recommended for use in an 838GM, and have tried pairs of 256mb, 512mb, and 1gb sticks thus far, so there shouldn't be any compatibility issues. Also tried updating the BIOS, but the latest version is from 2006, and I found that this PC already has that version.
So what are my options now? Are there any BIOS or jumper settings I'm overlooking? I've done a bit of research on the 'net, and it seems like nobody has ever had any problems upgrading the memory in their 838GM PCs.