How much does performance suffer when using a single DDR module?

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I have a Dell Dimension 8300 that is still trucking along. A while ago I had ugpraded to 2x1GB in it. Over the weekend, one of the modules died, so I went and bought another 2x1GB (to run in matched pairs). I have noticed from time to time that memory heavy applications (GIMP, etC) do get a little bogged down with only 2GB of RAM. My question is, am I better off pulling the 'odd' module, so the system will only have a matched pair, or leaving the odd module in, and having 3GB (instead of 2GB) of RAM?

Aaron

Posted 2013-12-09T21:20:50.237

Reputation: 310

No definite answer for this one without doing a lot of benchmarking, determining what your bottleneck is, your use pattern, etc. Generally speaking though, if you're maxing out the 2 GB, then the extra GB will likely be better than running 2 GB dual channel, and relying on swap . . . – ernie – 2013-12-09T21:46:13.193

So generally speaking, it's not 'catastrophic' (50% performance hit) to run with the extra GB as a single? – Aaron – 2013-12-09T21:48:41.137

You're usually not using full memory bandwidth, so in most cases, you won't see a big performance drop. If you're swapping frequently, then the memory bandwidth becomes a non-issue, as disk speed will be the limiting factor. I'd focus on figuring out if you're swapping, and if so, more memory will win out over dual-channel. – ernie – 2013-12-09T21:53:07.913

Answers

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The loss of dual channel does have a significant impact on memory performance, but that only has a small impact on overall performance because performance is rarely determined by memory throughput. One would expect that the significant change in memory size would prevail because more memory means less disk I/O, and disk I/O often affects real world performance. I'd leave the odd module in.

David Schwartz

Posted 2013-12-09T21:20:50.237

Reputation: 58 310