XFX 680i LT RAM Question (PC6400 vs. PC8500)

[kykartracer]

I am a bit confused here. I have the XFX 680i LT motherboard and according to the specs on Tiger Direct it will only support PC6400 (800 MHz) RAM. I went to their website and looked at the specs for this motherboard and it says you can run PC8500 on it. I am a bit confused as to which one is right.

Also, I have the Corsair XMS2 DHX PC6400 DDR2 800MHz Memory in the computer right now (http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3089875&CatId=2261). Can it be overclocked to the speeds of the PC8500 with latencies of 4-4-4-12?

Would I be better off overclocking the above RAM or getting the CORSAIR Dominator DHX PC8500 DDR2 1066MHz Memory (http://www.newegg.com/Product/Product.aspx?Item=N82E16820145043).

 

[GhislainG]

You can't overclock the RAM and keep the 4-4-4-12 timings. If Corsair had to increase timings and voltage to overclock to 1066, you can't expect DDR2 RAM that's not certified to overclock to that spped to use more aggressive timings. You'll have to use the timings and voltage of the overclocked Corsair Dominator DDR2 1066. The performance difference between 800 Mhz at 4-4-4-12 and 1066 Mhz at 5-5-5-15 is 1-2 percent at most. You'll have to run benchmarks to see the difference. With the risk of lower system stability, is it really worth it to you?

 

[kykartracer]

I thought I read on here somewhere that people were getting near 1066 speed out of the PC6400 and still keeping their timings down lower than 5-5-5-15??? I know people are saying they are overclocking the same RAM I have to 4-4-4-12 with 1000 MHz according to what they posted back on Tiger Direct.

 

[GhislainG]

I only found one reviewer that claims that they worked at timings of 4-4-4-12 at 1066Mhz. You can't increase the frequency from 800Mhz to 1066Mhz and expect to keep all other settings the same. Manufacturers usually have to increase the timings and voltage to make them work at higher frequencies, e.g., 6-6-6-21 at 2.2V.

The specs on the memory that you have (http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3089875&csid=ITD&body=MAIN#detailspecs) are:

- Memory Speed: 800MHz PC6400
- Memory CAS Latency: 5-5-5-18

If they ran at higher frequencies and tighter timings at 1.8V, Corsair would sell them as having those specs (and you couldn't buy them for $10 after reabate).

 

[jitpublisher]

You will never, EVER notice the difference in speed between 800mhz and 1066mhz memory. And any speed difference at all can only be seen in benchmark programs, and it is small. 0-5% at the very best.
No matter what the buss speed of memory you run, it all ties back to the FSB on Intel processors. No matter what you run, it has to be divided back to the original FSB spec. The only reason to have 1066 memory is if you are overclocking the FSB past 400mhz.