Strange memory issue.

Ok This question is for my friend so bare with me on lack of hardware info.

My friend has been getting crashes on his machine when he plays a game or does anything memory intensive. Just a random hard reboot.

Recently he and I have been playing Diablo II and this is when he noticed it becuase he hasnt played games untill now since his memory upgrade.

I ran Memtest on his memory and it began to get errors. I figured it was afaulty DIMM so I pulled one and ran it again, no errors. So I swapped em, no errors!!! WTF? I put them both back in and ran memtest again, full of errors. He had this problem before when he added a 256MB dimm to his 512MB. He asked me to try the 256MB in my PC too see if it was faulty. I did and it checked out. I eventualy ended up buying it from him.

The issue then again arose when he added another 512MB dimm for 1GB

The machine runs an older asus board that supports both Pc100/133 SDRAM and DDR dual channel. He has 2x 512MB DDR installed. It runs a celeron D socket 748 1.7GHz. It is not overclocked.

Usually on motherboards that support both kinds of ram like that have jumpers to set the correct voltage for whichever ram is installed. Check the manual if he has it or check the asus website to check the correct voltage settings for the ram that is installed. I think that might be the culprit. GOOD LUCK.

The power supply may not be enough for more than one RAM module.