Ram Question for 790x chipset

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manwe42

Weaksauce
Joined
Oct 13, 2002
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I just built a system with a Gigabyte GA-MA790x-UD4P, 7750 BE, and 2 GB Corsair Dominator DDR2 1066.

My intent was to upgrade to 4GB Later, as i have 2 open ramslots. But, now ive heard that populating all 4 ramslots (4x 1GB sticks) will result in the system becoming unstable at 1066 speeds. Basically that i would have to slow it down to 800-900 mhz.

Im wondering if theres any truth to this, or if it only effects certain Motherboard brands, or if its just random.
 
It just depends, certain boards have their bioses programmed to drop to 800mhz because they claim it is a "CPU limitation". Believe it or not, due to the low latency inherit to the integrated memory controller design, the difference between 800 and 1066 is minimal. You might also gain the advantage of running cas 4 at 800 instead of cas 5 at 1066. Just so you know, bios F2b will unlock the third core on a 720 BE (not sure about the 7750).

Good luck with your build.
 
Interesting. I actually lucked out on my proc and ram, got em for free...seems like they are pretty good parts, the cpu at least. Looks like i have some experimenting to do. :D
 
The limitation has more to do with how many banks of memory are on each stick. With single sided sticks should be no problems, but double sided sticks across 4 dimm slots put a real strain on imc and you might not be able to compensate with volts to keep the ram running at the higher speed.
 
i think i do have modules on both sides with this ram....Does this problem only effect the clock speed? Or would it also effect the memory's ability to run at a lower frequency but possibly at cas 4?
 
it wont slow the cpu down or anything.. it will just run the ram at ddr2 800 dual channel instead of ddr2 1066 dual channel..
 
Whether set manually or not, on some boards the bios will not run them at 1066. Some boards just can't handle it even though the cpu can physically do it.
 
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