I have two memory slots in my Sony Vaio laptop, one of which came with 256 MB installed. Almost 6 months ago, I put in another 512 MB (DDR266 SODIMM).
I noticed this week that the RAM being reported is 640 MB, not 768 MB as it should. The total amount possible is 1 GB. Using the RAM configuration detection utilities from memoryx, I found out that the two banks are being reported as 512 and 128.
Before adding the 512, my computer used to report 256 just fine. That 256 MB is the one shipped with the laptop so I wouldn't think there are any compatibility issues with it. So I'm not sure why it is not recognizing it in full now. It's being reported as a total of 640 MB in the BIOS too (not just Windows XP).
I cannot say for sure that it was recognized as 768 MB ever but I think it was. I don't believe I've done any BIOS upgrades. To make sure that I hadn't done any upgrades which caused part of the RAM not to be recognized, I checked the upgrade version of BIOS offered on the Sony site, and found that mine is not one of those upgrades.
Any ideas on what I could try?
Computer Make: Sony Corporation
Computer Model: PCG-FR720(I)
Computer Version: 01
Motherboard Model: Q51-Project
Motherboard Version: 01
CPU: AMD Mobile Athlon XP 1.66Ghz
Installed Memory: 2 slots: 128 MB, 512 MB
Matched - Machine: VAIO PCG-FR720
Matched - Model: http://www.memoryx.net/sovapcme297.html