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Old May 17, 2008, 06:57 PM
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3oh6 3oh6 is offline
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Default Dual 32M OC Report: 790i

We have finally arrived at the heart of the 'Original OC Report', the dual 32M SPi overclock testing. As the name suggests, all results listed in the chart below have passed dual 32M SPi using HyperPi 0.99b. I am not claiming any further stability than what is shown in the screen shots. Single 32M SPi will likely be higher and full Prime Blend, HCI Memtest, or 3D stability may be lower. I have found that dual 32M SPi stability testing is a nice and quick way to find out where a kit of memory will fall. Further testing for more or less stability can then be conducted from these results.

Result Caveat #1 - Obviously not all retail samples of this memory are going to clock as good, at the same time, some will clock better.

Result Caveat #2 - This sample was supplied by Crucial for a review. I have confirmed with Sam Harmer (Crucial/Lexar Public Relations Manager) that all review samples from Crucial go out to reviewers are random retail samples. The marketing department simply puts an order through their retail department and the sample sent out is completely random and from the exact same pool of samples that would go out to any other customer ordering memory from Crucial. This memory is 100% not handpicked in any way.

Result Caveat #3 - Memory clocking results will vary from sample to sample of 790i motherboards we are finding. My 790i reference board seems to be a pretty decent one. On top of that, I have obviously modified the SPP voltage as well as the cooling. Keep this in mind when looking at results. The vSPP displayed in the Everest on-screen display is accurate with actual voltage being supplied as measured from the output coil with a DMM.

Result Caveat #4 - There are a lot of issues with 24/7 stability/corruption and the 790i motherboards, particularly 3D gaming and watching movies of a certain type. Don't read more into these results than they are, I am only showing dual 32M stability, nothing more. If you are considering a 790i board for a daily machine, then please be sure to visit manufacturers forums like EVGA to see exactly what the issues are before spending your hard earned money.

Result Caveat #5 - The vDIMM listed for each overclock is accurate with a DMM measurement from of the open DIMM slots at the first VDD pin beside the key in the DIMM. The ground used is the lower left hand ground plane at the motherboard mounting hole. The DMM used is UEI DM393 that is calibrated yearly and was last calibrated in March of this year.

Now that I have that out of the way, here is what this monster kit cooked up:

6-6-5-X 1T:
NVIDIA 790i:
Click link for full size screenshot...
780MHz :: 1.90v | 797MHz :: 1.95v | 813MHz :: 2.00v | 830MHz :: 2.05v | 846MHz :: 2.10v

Well there you have it. This kit obviously doesn't mind 6-6-5 and going to 6-6-6 didn't gain much over a couple MHz if that. At stock voltage of 1.90v this kit ran a comfortable 780MHz and climbed to a very respectable 846MHz with 'only' 2.10v. The 24/7 ceiling for DDR3 and these D9 based Micron ICs has been all but agreed upon to be 2.10v. Even then, we are not 100% sure they will last, 2.00v is the safer 24/7 voltage. For benching, however, 2.10v seems to be more than fine and even 2.20v appears to be pretty acceptable for certain periods of time. With this kit though, I will stay at 2.10v until all of the other testing for the review is complete, then perhaps we will see an update at 2.15v and 2.20v.


7-6-5-X 1T:
NVIDIA 790i:
Click link for full size screenshot...
905MHz :: 1.90v | 925MHz :: 1.95v | 945MHz :: 2.00v | 967MHz :: 2.05v | 981MHz :: 2.10v

Again, going from 7-6-5 to 7-6-6 gained next to nothing for frequency which is consistent with other kits of D9GTR/D9GTS that I have clocked. I was kind of hoping for a bit of headroom with a tRP of 6 as the 790i is suppose to take off at 7-6-6 versus 7-6-5 but I just didn't find that with these modules. This kit is definitely going to be 7-6-5 1000MHz single 32M stable, but the real question is going to be whether or not tRFC will be able to come down. As it stands, for dual 32M stability, it had to go up to a rather high 75 for the maximum frequency hit. In fact, for any decent clocks at 7-6-5, tRFC had to come up to 65 which really hurts 32M SPi performance.


8-7-6-X 1T:
NVIDIA 790i:
Click link for full size screenshot...
1021MHz :: 1.90v | 1045MHz :: 1.95v | 1068MHz :: 2.00v | 1088MHz :: 2.05v | 1112MHz :: 2.10v

This is where things got really fun. I just recently posted my G.Skill PC3-12800 (D9GTR based) results which showed an 1100MHz single 32M run and 15K Everest Read result on this motherboard. This memory took that a big step forward cracking out an 1112MHz dual 32M SPi run which up to this point has never been seen to my knowledge. To severely understate these results one would say they were nice. To appropriately state these results, one would have to use terms like incredible, un-believable, and a few adjectives that will simply show up as bananas. At some point I will be showing the max single 32M run with this kit at 8-7-6 but I want to save that for a really crazy run at max frequency of this setup...so look for that down the road a little bit.

Last edited by 3oh6; May 19, 2008 at 08:15 AM.
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