Frequent BSODs (after much debugging)

If you use two unlike memory modules, you can have this problem. On many motherboards, you must use modules that are the same frequency and the same storage characteristics.
If you use a DDR2 PC 4200, for instance, you may have to use a second DDR2 PC 4200 for the second module. You cannot, in some motherboards use a DDR2 PC 2700 1 GB and and a DDR2 PC2700 512 MB module.
Nor can you use a PC2700 and a PC 3200 in some boards.
Other boards do not care.
But to assure the best chance of everthing working together, used matched sets of memory, that come in a box together. If you cannot do that, use the same size, and the same frequency.
Yours may simply be too different...
Some are third tier memory, some are first tier memory.

Good to hear this .

Yes you are correct it would have made it unstable if the 512mb card was in.

They both run very differently, Memtest86 tests specific addresses designed to see if the RAM is faulty (Basically some very complex Addresses in some Tests and quite simple Addresses in others I believe), it is known that Bad RAM can pass Memtest and this proves it but it seems Prime95 is a good second test for the RAM.

Prime95 searches for something called Mersenne Primes or something like that and so is very picky if it doesn't find the correct calculation from using the CPU to calculate this and then it passes it onto the Program (On RAM) and so then finds the error.

Since it is XP it would run on 512mb quite easily it would be able to run a couple of programs at the same time say a Virus Scan and continue Web Browsing. I don't know about McAfee it might need a bit of RAM to run.

Raybay, good call. I made sure that when I bought the second stick of RAM that it was exactly the same (Kingston 2100, same ECC, etc.) even down to the part number, minus the size of course. So I don't think that was the problem...but your second idea that the board might not be able to handle two sticks that aren't of the same size could be what's going on there. Unfortunately, the only way to really test that at this point would be to buy another 512 stick and try it with the old 512, which is pretty much a waste of money at this point for me because I'd buy another 1 GB instead. But this is really informative and good to know.

woody1191, my guess you're right that the old stick passed MemTest86+, but not Prime95. In the next few days I'm going to try to but them BOTH in and see if it BSODs again. My results (I think) would look like this:

If it works fine, then perhaps 512K just wasn't enough RAM (for some sudden reason that I may not ever figure out).

If it doesn't work fine, then a) the 512K stick is bad or b) my mobo can't handle two sticks of different size. Unfortunately I may never know the answer to that if this is the case, but if it works on the new 1 GB stick I'll still be happy!!

Will post back after testing.

Thanks for both your input!!

Okay...I now have both the new 1 GB stick in and the old 512 MB stick in with these results of running Prime95:

The first test (Small FFT’s) ran for over 13 hours and never crashed…I had to eventually stop it manually.

The second test (Large FFT’s) crashed after 5 minutes.

The third test (Blend) crashed in under 1 minute.

Also, the BSOD’s are back and so are the IE crashes!

So, it seems to me that one of two things are the case here:
a) The 512 stick is indeed bad.
b) It was crashing before because there wasn’t enough RAM with the just the 512 stick, and it is crashing now because my mobo can’t handle two different sticks that aren’t exactly the same size.

Thoughts? I’m almost positive it’s got to be option a) myself. Since there’s no way to narrow it down between a) and b) conclusively without buying another 512 stick, it looks like this is as far as the testing goes. But that’s fine for me. Either way, placing just the new 1 GB stick in solves my problems!

if u just put in 2 gig. u will have all the mem. any 32bit system will use.

Well the point A you made is half right because yes the Stick is bad but also mixing the RAM sticks like that can cause problems if you get 2Gb like nickc said then they have to be both exactly the same, e.g. Same Manufacturer, Same Memory Size, Same Bus Speed etc. Basically identical.

The Small FFT's test mainly tests the CPU the other 2 test a bit of RAM and Mainly RAM, i may have mentioned this before but just to confirm here.

Sounds good. I'll try to obtain another 1 GB stick just as soon as the budget allows.

This thread was quite successful! Thanks so much for your help everyone!!