23 November, 2007

GRT-815M memory upgrade

After 4 years I have found the prices of the compatible SO-DIMM reasonable, so I have decided to replace the original 2x256MB on my computer with 2x512MB.

The SONY VAIO Online support web page is not that helpful - it gives you very basic information
Maximum Memory: 1024 MB
Memory Type
: SO-DIMM - 266Mhz (DDR)
and not much on the compatibility...

For instance, a very quick check on Crucial gives you very detailed and crucial information!
- Each memory slot can hold DDR PC2700 with a maximum of 512MB per slot.
- Your system does not support dual channel.
-
Your system does not support ECC. Because ECC and non-ECC modules should not be mixed within a system, install the same type of modules that are already in your system.
So don't look for 1GB modules - they simply won't work... ...as well as a small catch
"Because DDR memory is backward-compatible, you can safely upgrade your system with any of the guaranteed-compatible DDR speeds listed below, even if your manual calls for PC1600 or PC2100 speeds."
the listed one was:
CT368470 512MB DDR PC2700 • CL=2.5 • Unbuffered • NON-ECC • DDR333 • 2.5V • 64Meg x 64
Well, the reasonable price I have found was for DDR400 (PC3200) and that one was not recognized by the BIOS or the motherboard - complete hang, the computer was not showing even the BIOS screen. To resolve the problem I have replaced one of the new 512MB modules with the one of the old 256MB to impose the lower frequency settings of that one. It worked, although depending on which slot is the old one the BIOS was recognizing 512MB or 768MB. So this was quite good guess that if I replace the old 256MB, in this odd configuration, with 512MB (DDR266 PC2100) or (DDR333 PC2700) it will do the same work, so I did it.

This is how I end up finally after I have exchanged one of my newly bought modules for an old one - DDR333:
512MB PC3200 DDR400 A-data
512MB PC2700 DDR333 Kensington



Memtest showed insignificant speed up from 987 MB/s with the original Infineon memory to 1054 MB/s with the final configuration. As expected, the computer performs slightly faster while loading programs for the first time, really fast once they are in the memory, dramatically reduces the HDD I/O that also helps to keep the computer cooler (I guess every time a file is accessed from the HDD it is scanned by the anti virus program). In Windows, the memory status reports that nearly half of the memory is free that proves that 512MB configuration leads to inevitable frequent swapping. After all that, one can easily discover that the slow HDD remains the major reason for the slow down after the memory upgrade (in an earlier post, I have already mention about Linux performance when the root folder is mounted on a external disk). Anyway, it is a real pleasure to work on the computer now.

So finally, keep in mind that you'd better stick to DDR266 and DDR333 to avoid similar annoying problems.

Tip: If you are running out of space on the disk and you are using the windows hibernate function, adding an extra memory will also make your "hiberfil.sys" equivalently larger. Make sure you have enough free space after the upgrade to avoid performance slow down because of that.