# Computer memory - 2x512MB or 4x256MB?

**URL:** <https://boards.straightdope.com/t/computer-memory-2x512mb-or-4x256mb/288157>\
**Category:** Factual Questions\
**Created:** [February 3, 2005, 1:19pm UTC](https://boards.straightdope.com/t/computer-memory-2x512mb-or-4x256mb/288157 "2005-02-03T13:19:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Earthworm\_Jim](https://avatars.discourse-cdn.com/v4/letter/e/f07891/32.png) [@Earthworm\_Jim](https://boards.straightdope.com/u/Earthworm_Jim)\
**Post date:** [February 3, 2005, 1:19pm UTC](https://boards.straightdope.com/t/computer-memory-2x512mb-or-4x256mb/288157/1 "2005-02-03T13:19:18Z")

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I’m looking to put 1GB of memory in a new PC. Other than “upgradability”, is there any reason to choose 2 512MB dimms over 4 256MB dimms, or vice versa?

My gut instinct is that you’ll get (slightly) better performance using all 4 dimm banks instead of just two.

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**Author:** ![RandomLetters](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@RandomLetters](https://boards.straightdope.com/u/RandomLetters)\
**Post date:** [February 3, 2005, 1:34pm UTC](https://boards.straightdope.com/t/computer-memory-2x512mb-or-4x256mb/288157/2 "2005-02-03T13:34:52Z")

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You would only gain in performance if you had quad-channel memory memory controller; IIRC, the only “mainstream” chips that would allow this would be a dual Opteron machine - and if you need a dual Operton, you need more than a miserly gigabyte of RAM. 😉

Almost every other motherboard uses either dual channel memory or single channel; note that with the Athlon 64 chips, there is only a slight performance gain by going dual channel; I don’t know about Intel’s stuff.

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**Author:** ![LordVor](https://avatars.discourse-cdn.com/v4/letter/l/90ced4/32.png) [@LordVor](https://boards.straightdope.com/u/LordVor)\
**Post date:** [February 3, 2005, 4:19pm UTC](https://boards.straightdope.com/t/computer-memory-2x512mb-or-4x256mb/288157/3 "2005-02-03T16:19:25Z")

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**RandomLetters** is right, most current motherboards can only talk to one or two dimms at a time, so having memory in four dimm slots isn’t going to gain you any performance.