Upgrading DDR2 ram from 1GB to 3 GB slot question - mixing ram

[Firebot]

The company I work for is doing a mass upgrade rollout to upgrade from 1GB (1x 1 GB DDR2) to 4GB (2x2 GB DDR2) on their computers, but it ran into the dreaded Windows XP 32-bit snag where only 3 GB of ram is recognized. Now here is the dilemma since I'm not sure how much the impact will be of mixing different ram and I don't work with memory much (currently plan is to keep the 1GB and simply put in an extra 2 GB due to the 3GB limit)

What is the optimal solution in terms of performance as I'm not quite sure? 4 slots, colour code channel A 1-2, and colour code channel B 1-2 are the slots available. I'm not sure if the slots make a difference or not if the memory will be different.

1) Take out the 1GB ram currently in and put in both 2 x 2GB in dual channel mode in channel A using only 3GB

2) Keep the 1GB in channel A-1 and put a 2GB ram in Channel A-2 (same channel)

3) Keep the 1GB in channel A-1 and put a 2GB ram in Channel B-1

If 1 is still the best choice, does the performance boost versus knowing the 3GB limit warrant the extra cost of putting in 2 x 2GB or is it negligeable?


BTW the timing for the 1GB is 5-5-5-12 and the timing for the 2GB stick is 6-6-6-12

 

[goobernoodles]

I doubt you're going to notice a performance hit due to running single channel vs dual channel. If you're trying to save money - I'd just go with the 1Gb + 2Gb (single channel) setup.

 

[VirtualLarry]

.
BTW the timing for the 1GB is 5-5-5-12 and the timing for the 2GB stick is 6-6-6-12

Depending on the motherboard, this could potentially be an issue, especially if the stick in the first slot is the faster timings.

Do big-box OEM computers even allow you to set the DRAM timings?'

 

[mrjoltcola]

I haven't booted into XP lately, but you actually get a bit more than 3.0GB, I think it is 3.4GB, so I'd opt for putting in the 2 x 2GB anyway, that .4GB can make a difference depending on what you run. That is about the amount that the XP OS takes up.

Since your company is doing this on many PCs, are they considering future upgrade of the OS?

For my firm I ordered 4GB on all my old Dell Precision 390 stations knowing we'd eventually go to 64-bit. We ran a few years with 3.4GB on XP, now everyone is on Windows 7 x64 gets all 4GB, though it probably evened out with Windows 7 using more RAM from the start.

 

[mrjoltcola]

Do big-box OEM computers even allow you to set the DRAM timings?'

None of my Dells allow it. All set in stone. I have Core 2 Duos that I could get 3-400Mhz out of if we could...

 

[Firebot]

I doubt there is any OS upgrade in the near horizon since there are bigger priorities right now, but the thought of being a little more future proof is good so I'll mention it, since 4 GB is what was planned originally. Thanks all for the comments. Memtest 86 ran smoothly on the couple of test machines with the 3GB setup so will see what the decision will be in the end.