First post, by feipoa

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I have 4 GB of memory spanned across four DDR400 modules. If I use some older, low memory AGP graphics card, all 4 GB of my system RAM is addressed. However, if I install a newer AGP graphics card, say a GF6 with 256 MB of RAM, only 3 GB of my system memory is addressed. If only 3 GB is addressed, does my system memory still run in dual channel mode? If yes, what type of performance hit, if any, is there?

Last edited by feipoa on 2015-12-12, 22:52. Edited 1 time in total.

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Reply 1 of 3, by stuvize

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What OS are you running and is the GF6 a AGP card? the AGP aperture size can sometimes make system ram decrease in windows. I have 16gb of ram in my modern machine and dual boot with XP32 bit there is 3.27GB a ram addressable in windows and I never notice problems from lack of dual channel performance. When using a Creative sound card games with Dsound acceleration and EAX experience pops, clicks, hums and all sorts of problems if dual channel is not enabled, other things can cause this too but Creative states that dual channel memory is required for proper Dsound acceleration. I don't know of any way test it for sure but I think memory is addressed by ROWs first and COLUMNs second so data should be spread evenly across the modules regardless how much is realy addressed by the OS