annoying memory problem

[calsonic]

ok so i had 2 512mb sticks of ram in my pc's, and i just installed an additional 2 sticks of 1gb each. of course windows is only recognizing 2.5GB.

supposedly this is a well documented problem, however i cannot find a solution anywhere for systems using 64 bit XP. i have tried adding the /3GB switch to the end of the boot file and there is no "mapping" setting in my bios.

any help is greatly appreciated.

 

[eyeCpc]

You may have a bad 512 sitting in a slot or simply mismatched memory to start with. Even a 32bit edition of XP will readily see upto 3.12-3.2gb of memory out of a 4gb total.

The hardware mapping is strictly OS/32bit kernel not any bios problem. Windows is simply mapping out a certain amount of memory addresses to hardwares taking away from the total amount of ram available for games, programs, etc. there.

 

[calsonic]

so even when i had only the 2 512mb sticks installed, windows showed
1 gb it won't show 3 gb even if i have 3 gb?

 

[peterhuang913]

Switch the 512's around. You didn't post any other information -.-

 

[calsonic]

my mobo is a Sapphire PC-A9RD580Adv with an Athlon 64 X2 3800+

i switched the sticks around and it still shows 2.5GB

when i put just the 2 new1 gb sticks in it showed 2GB

 

[eyeCpc]

With two 512s you are only going to see 1,024mb until you add another 2gb of memory. That's simple math there.

For seeing only 2.5 out of 3gb besides one of the 512s suddenly going bad a mismatch being seen with the new memory like timings will see problems. With DDR memory on an older system mixing single sided dimms with the dual sided memory seeing IC chips on both sides of a memory module will also cause problems.

The last part sounds more likely since the pair of new dimms are being seen fully when run by themselves pointing out at a clash between the two different pairs. 2gb is better then one!

 

[peterhuang913]

Try running the 1GB again.

Also, it's than and not then.

 

[calsonic]

With two 512s you are only going to see 1,024mb until you add another 2gb of memory. That's simple math there..

i was just trying to say that the 2 512 sticks were being detected as 1GB by windows and that the 2 1GB sticks were being detected by windows as 2 GB independently, and that they were all working.

they are all 184-Pin DDR 400 Dual Channel modules. same brand also

 

[eyeCpc]

Is one set a pair of single sided dimms? You are apparently seeing a clash of some type between the two pairs of dimms bought at separate times. The loss of 512mb when both pairs are installed points at a mismatch of some type making them incompatible with each other while working separately.

 

[calsonic]

they are both dual sided