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Topaz · Apr 16, 2008, 10:27 AM

I was recently told that I couldn't replace one of my two 512MB memory chips with one 2GB chip thus giving me 2.5GB ram. However having visited the Crucial web site I now learn that ...

"Q: Do I have to install matching pairs?
A: No.
No, you can install modules one at a time, and you can mix different densities of modules in your computer. But if your computer supports dual-channel memory configurations, you should install in identical pairs (preferably in kits) for optimal performance.

Q: Does my computer support dual-channel memory?
A: No.
Your system does not support dual channel.

Q: What memory goes into my computer, and can I mix speeds?
A: DDRII memory with support for DDR2 PC2-5300 speeds.
Because DDR2 memory is backward-compatible, you can safely upgrade your system with any of the guaranteed-compatible DDR2 speeds listed."

As this is a basic contradiction of what I was told, is it true? Can I install non matching pairs?

Simon · Apr 16, 2008, 10:30 AM

You can install non-matching pairs.

Topaz · Apr 16, 2008, 11:18 AM

Thanks Simon, although I guess that there might be a slight performance advantage in having matched pairs. I intended to install 2 x 1GB chips but now wonder if the performance of a 2GB chip plus my existing 500MB would give any significant improvement. Mmmm....

chipchen · Apr 16, 2008, 11:30 AM

more RAM the better. more RAM the better.

mduell · Apr 16, 2008, 07:29 PM

If your workflow/applications are sensitive the memory bandwidth then you may see lower performance. Most workflows/applications are more sensitive to memory capacity than bandwidth, so it's a good tradeoff.

Simon · Apr 17, 2008, 02:15 AM

Originally Posted by Topaz

Thanks Simon, although I guess that there might be a slight performance advantage in having matched pairs. I intended to install 2 x 1GB chips but now wonder if the performance of a 2GB chip plus my existing 500MB would give any significant improvement. Mmmm....

More RAM is better. Get a 2 GB DIMM.

P · Apr 17, 2008, 09:59 AM

Originally Posted by Topaz

Thanks Simon, although I guess that there might be a slight performance advantage in having matched pairs. I intended to install 2 x 1GB chips but now wonder if the performance of a 2GB chip plus my existing 500MB would give any significant improvement. Mmmm....

This has been debated endlessly. Barefeats eventually tested what happened, and their result (don't have the linky here) was that more RAM is better in every case except for the graphics performance with integrated graphics, where matched DIMMs had a lead.