64-bit machine with 5.12 GB RAM, only 4.2 GB usable

Electrode · 11-17-2009, 04:56 PM

Running 64-bit kernel 2.6.31 on a dual Socket 940 machine. 5120 MB of RAM is installed (2x1GB + 2x512mb on one CPU, 4x512mb on the other). BIOS detects all of it properly.

dmesg shows that the kernel seems to be aware of it (note line 240 of the attachment), however only about 4.2 GB (exactly 4224032k according to top) seems to be usable.

Any ideas?

fotoguy · 11-18-2009, 02:29 AM

Are the 512mb ram sticks the same speed and brand as the 1gb sticks, I know 5-10 years ago having 2 different brands and speeds caused a lot of issues with systems, I know I had a few myself.

Electrode · 11-18-2009, 02:06 PM

Quote:

Originally Posted by fotoguy

Are the 512mb ram sticks the same speed and brand as the 1gb sticks, I know 5-10 years ago having 2 different brands and speeds caused a lot of issues with systems, I know I had a few myself.

Both of the 512mb sticks on each side are the same make. Micron on one, Infineon on the other. All PC2100.

Synt4x_3rr0r · 11-18-2009, 03:50 PM

Yeah the best thing to do is to get all the memory sticks at the same time and the same brand on all of them.
But everything should still show up. I have mixed brands many times and I've never had this problem.

In worst case it could be that one of the sticks are starting to go corrupt.
Edit: But even then it should still show up. Only that apps would randomly crash and not behave as intended. This is a weird problem :S