Hey Guys, I am curious as to how the maximum amount of memory is detected/utilized by Windows in general. I am currently referring to a 3 year old desktop with Windows XP Home 32-bit. I have 3 GB of DDR2 PC2-5300, 667 Mhz and also an ATI Radeon HD 4890 pci x16 which has 1 GB of DDR5 dedicated memory on it. As I understand it, Windows XP 32-bit can only recognize either 3.5 or 4 GB of ram maximum. Does the ATI graphics card I have count toward that maximum, making windows see my total ram as 4 GB now. The main reason why I want to know leads to the second part of my question. I am looking to upgrade my system ram to DDR2 PC2-6400, 800 Mhz. I don't know if I should just ad 2 GB of the DDR2 PC2-6400 in place of all of the older DDR2 PC2-5300 ram or if I should ad more than 2 GB of DDR2 PC2-6400, would there be any performance issues as far as windows not recognizing part of it, if I had 4 GB of DDR2 PC2-6400, 1 GB per each of the 4 memory slots which is the max the motherboard can take on that note. Thanks to anyone who reads and/or reply's to this rather long question!
The XP/32 recognizes some 3.3G of RAM. This has nothing to do with the video card's memory. There's no real difference between 800 Mhz DDR2 RAM and 667 Mhz DDR2 RAM, 667 is fine. You can get one more stick just like those you have but it will make a (small) difference only if you change the OS to, say, Win7/64 bit.
A 32 bit OS has the capability to address 4GB. of RAM this includes the reserved system memory space and the video page file addresses leaving about 3.25 GB. of address spaces for system RAM - the video memory is swapped in\out of the pagefiles by the videos card and will not change depending on the amount of actual RAM on the video card (the system does not see the actual amount of video memory that is handled by the GPU itself so whether you have a 256MB or 2 GB. video card they will be seen as using the same amount.
As far as adding more RAM what configuration do you currently have ? (3x1 gb. or 2x1GB. and 2x512MB ??) -- IF you have 3x1GB. it might make sense to buy another 1x1GB module to match the ones you have since that would be fairly inexpensive and would then allow your system to run in dual channel mode (if you have 3 modules you are running in single channel mode which will slow the memory throughput) but if you have 2x1GB and 2x512mb. filling all 4 slots you will already be running in dual channel and changing 2 512mb modules with 2 1GB modules is more expensive and the result would only get you about 256MB more useable memory so not really worth it -- Also along those lines the difference in pc2-6400 and pc2 5300 will be barely noticeable so replacing all 4 gbs of memory makes even less sense considering you will barely notice any improvement for the cost.