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E6750 & 2GB Corsair DDR2 1066

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November 27, 2009 3:10:17 AM

Hey guys, I've had my computer for about 2 years now, but I've got to wondering if I am using my RAM to its capabilities. I have set my CPU to a bus speed of 400 MHz with a multiplier of 8 so its running at 3.2 GHz. I have 2 gigs of corsair dominator DDR2 1066 (PC2 8500) and set it to run at a 1:1 ratio with my CPU bus speed and 5-5-5-15. I have not fooled with any voltages. I have noticed CPU shows my "max bandwidth" under SPD as PC2 6400 (400 MHz). Isn't this incorrect? Shouldn't it be PC2 8500? Am I not using the full potential of my RAM?
a b } Memory
a c 172 à CPUs
a c 197 K Overclocking
November 27, 2009 2:20:06 PM

I always run my memory at 1:1. That is the FSB freq to memclock ratio is one to one. That means that the memclock is twice the FSB freq. It's a little confusing. Running memory slower costs performance. Running memory faster does not give you much if any real world performance increase and it can lead to higher instability.

And let me say, "There ain't no such thing as DDR2-1066 RAM." Got your attention now, yes? :)  DDR2-1066 RAM is simply DDR2-800 RAM that has been tested to run at the higher speed, usually at an increased voltage and more relaxed timings. And most good DDR2-800 CL4 RAM will do this.

Here's a thread where some of us discuss this:
http://www.tomshardware.com/forum/251715-29-ratio-myth

At this point, you will gain more real performance by tightening the timings to, say, 4-4-4-12 than by trying to OC the RAM.
a b } Memory
a b K Overclocking
December 1, 2009 2:47:48 PM

In some applications you will benefit from running the memory faster than the CPU. However, I have tested it and never found more than about a 2%-5% gain. The only way to know for you is to run your memory both ways doing what you built your system for and compare the results. You should be able to set a differrent memory ratio in the BIOS and get 1066.
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December 3, 2009 11:14:26 AM

Does this apply to AMD chips with hypertransport, or the new Intel chips i5/i7 with QPI, and the memory controller directly on the CPU?
a b } Memory
a c 172 à CPUs
a c 197 K Overclocking
December 3, 2009 5:14:28 PM

My post is aimed a the Core2 users. Sometime later this year, I may build an LGA1366 i7 system.
December 13, 2009 3:18:46 PM

I plan on upgrading to have 4 GB of RAM to go with Windows 7 64-bit I'm going to be installing soon. I have 2 x 1 GB of DDR2 1066 right now. I'm not sure which would be the best way to go. My mobo has 2 DDR3 1066/800 slots and 4 DDR2 1066/800/667 slots.

1. Another 2 GB of DDR2 1066
2. 4 GB of DDR2 800
3. 4 GB of DDR3 1066
4. 4 GB of DDR3 800

Which do you think would be the best route to go? I built this computer 2 years ago with the option of upgrading to DDR3 available to me but I don't know if that memory is worth it or not.



EDIT: I looked in my BIOS and I have the memory SPD set to 2 to give me 800. If I put it on auto it shows something like 960. There is no 1066 option.
a b } Memory
a c 172 à CPUs
a c 197 K Overclocking
December 17, 2009 5:56:04 AM

Whoops.
"My post is aimed a the Core2 users. Sometime later this next year, I may build an LGA1366 i7 system. "
After the die shrink.
December 19, 2009 4:21:11 PM

I just lowered my specs to 4-4-4-15, still @ 800 MHz, didn't have to raise voltages. I had run 3DMark06 tests for 800 MHz, 960 MHz, and 1000 MHz, and progressively the scores were higher, but only giving me 0.2% increase @ 1000 MHz over 800 MHz.

I lowered my specs to 4-4-4-15 on 1000 MHz and had to raise voltage to required 2.1 V and it still would not post. So I decided to go back to 800 MHz (1:1) and try the 4-4-4-15. Average score was 6 points higher.

Go figure.
a b } Memory
a c 172 à CPUs
a c 197 K Overclocking
December 23, 2009 4:33:56 PM

Told you. :) 
December 23, 2009 6:20:58 PM

Yep, unless 3DMark06 isn't a good bench to test ram. I ended up ordering another 4GB (2x2) of DDR2 800 to throw in with my current ram. I'm using it at 800 anyway, so I may as well combine them for 6 GB.
!