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FSB 1066 vs 1333, DDR2 800 vs DDR3 1333

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August 26, 2007 3:15:04 PM

I was considering purchasing the Commando mobo, but the FSB is limited to 1066 megs. I plan to use the Intel E6850. Would there be a big increase in performance switching to a mobo that has a 1333 meg FSB?

I have seen some reports saying there isn't much performance increase on a 1333 FSB mobo when the memory is changed from 800 meg DDR2 to 1333 meg DDR3. Would there be a noticeable difference using 1333 meg DDR3 memory instead of 800 meg DDR2 memory?

If buy a mobo has a 1333 FSB, and 800 meg DDR2 memory is used, will the FSB be running at 1333 meg? Would the 800 meg DDR2 memory be a noticeable bottleneck?


Dave
August 26, 2007 4:26:39 PM

The C2D processors aren't really FSB bottlenecked so the increase from 1066 to 1333 is only a few percent for a like CPU comparison. Example: E6700 vs E6750 - Both run at 2.6G and won't be a very noticable increase. You will get a larger and more noticable increase from a E6700 vs E6850 though because you will be running with a faster FSB *and* you will be running at +400MHz. If you overclock, then the difference is negligible as both processors E6700/E6750 and E6850 can overclock to similar speeds.

As far as memory frequencies go, 1066 vs 1333, DDR2-800 should work in both scenerios just fine as both FSB run at a 1:1 ratio are within the DDR2-800 spec (266x2=533MHz vs 333x2=667MHz are still within the 800MHz ceiling). If you want to run DDR2-800 at it's full potential of 800MHz, then you will be running 266x3=798 or 333x2.5=832.5 which the later will run slightly out of the DDR2-800 specifications by 32.5MHz. Most high quality DDR2-800 modules shouldn't have an issue running outside of spec up to a point with normal timings so you should still be fine.
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