QUOTE(berus_jamban @ Jan 29 2009, 05:40 PM)
Good day CQ40 series notebook users!
Just curious...
Scenario:
According to Compaq Presario CQ40-134AX Notebook PC (NE621PA) - Specifications, the maximum memory you can put in is 8GB. Since there's only 2 memory slot, what I understand is that you have to put 2 x 4GB PC667/800 DDR2 to accomplished the max. I'm planning to get 1 x 4GB PC800 or 2 x 4GB PC800.
Questions:
Do I need to run 64bit OS to fully utilize 1 x 4GB PC800 in one slot? Because I read in the thread that we have to use 64bit OS in order to fully utilize 4GB (2 x 2GB PC800 DDR2) otherwise it will end up with only 3. something GB of RAM. Or does it only apply on dual channel only, which in this case the above 4GB (2 x 2GB PC800 DDR2)?
I hope that someone will answer my question ASAP. Will buy it tonight. Thanks in advance...

Wow, what price did you get for 4GB sticks? I thought of upgrading some time ago but too expensive, even now that the price of 4GB sticks has dropped a lot, the cheapest I have seen 2x4GB PC2-6400 (800MHz DDR2) for is around
RM 2000. Yep, that's 2000 not 200, about RM 1000 per stick.

AFAIK 32bit MS OSes from XP SP2 onwards (except server versions) have capped memory and drivers to 4GB (32bits), so if you had a gpu with 512MB of dedicated memory for instance then that would mean you would not be able to utilize 512MB of your main 4GB RAM.
If you want to see how much of your 4GB is available to your system you can check with
Task Manager under
Physical Memory Total.