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eVGA 680i and TWIN2X2048-6400C4 Sensitivities


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Hi Ramguy,


We're building multiple setups with eVGA 680i motherboards and TWIN2X2048-6400C4. Out of 4 packs (8 sticks) of the RAM we've seen two bad packs (verified on separate 965 and 975 chipset motherboards) which we RMA'd for replacement to the retailer. We've continued to test the other two good packs and have noticed some blips during long memtests. Here is what we've seen.


Setting the motherboard to auto RAM timings (via SLI and 0% overclock) and auto voltage (2.1v) we might get an error within an hour of memtest. On the same setup if we back the voltage down to 1.95v and set timings to manual but keeping the same auto timings for everything except for tWTR which we bump up from 8 to 9 we can run memtest without errors for 12hours.


On a seperate board/RAM setup using 1.95v and tWTR 9 might give us 1 error in 8-12hours of memtest but bumping to 2.0 might be error free.


So my question is do you have any suggestion on setting the sub-timings to something more relaxed? The auto settings seem to be more problematic than our tuned settings. We'd like to continue to run the primary timings at 800 4-4-4-12.


Other info: P25 BIOS, Default Auto sub-timings are:


tRRD: 3

tRC: 22

tWR: 5

tWTR: 8

tREF: 7.8us


Thanks in advance

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Using SLI and BIOS defaults results in memtest errors on 3 different eVGA 680i boards and 4 different packs of Corsair TWIN2X2048-6400C4 RAM. Testing a 5th new package of RAM today with batch code 07050424. The odds of them all being defective seems pretty high. Thus why I'm reaching out to the manufacturer for timing suggestions.
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That would suggest some other problem and I would suggest you contact our Tech support and let us try to help you. 800-205-7657.


But what is the complete system configuration of one of the failing systems, and did you get the latest bios and load setup defaults before you set the tested settings?

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Thanks Ramguy. I'll give them a call Monday.


I have made some progress. I took a look at the XMS qualification and testing post. On the 680i I was running everything based on the Auto SLI settings for memory timings and voltage. Alas, FSB Termination voltage is, by default, automatically set to 1.2v. The qualification post notes a Vfsb of 1.5v for this RAM is what you test with.


Initial retesting looks good. Up'ing Vfsb from 1.2v to 1.3v on one board/RAM setup yielded a 14hour clean memtest. The other two board/RAM setups failed at 1.3v. I'm now retesting them at 1.4. I hope they can handle the heat!

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I have the same problem with the same hardware,

EVGA 680i

Intel E6600


BFG 7900GTX (one of them)

WD 36gig Raptors (2)


The system posts sometimes, and not others. At the moment, I'm running the DIMM's in the black slots. Could you please post your bios settings.


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Hi m_pascar,


I'm testing multiple 680i boards and sets of TWIN2X2048-6400C4 so here is what I've now found that works (i.e., allows memtest to pass 12+ hours of testing) on all of the boards/RAM combinations that I've tried (i.e., the maximum voltage settings I've used).


RAM timings/voltage - You can set it in the BIOS a couple different ways yielding the same settings but I like to set the SLI to Expert and then under RAM timings to Optimal. This causes the BIOS to apply all the SLI EPP RAM timings and the RAM voltage will be auto to 2.1v.


FSB/RAM speeds - FSB 1066, RAM 800. Note that this is the non-overclocked default.


System Voltages - Auto everything (note ram should auto to 2.1v with SLI EPP). Manually set CPU FSB voltage to 1.4v.


So basically SLI EPP auto everything but manually up your CPU FSB voltage. That was the key for me. Corsair testing qualifies the ram at Vfsb 1.5v and Vdimm at 2.1v. My problems were with Vfsb at 1.2v. I have two boards that require 1.4v and one that is happy with 1.3v Vfsb. So you'll have to play around but you might want to try Corsair's spec'd 1.5v Vfsb and 2.1v Vdimm as a starting point.


I need to do more testing but I can say that up'ing Vdimm from 1.9v to 2.1v had a lesser effect in increasing stability than up'ing Vfsb from 1.2 to either 1.3 or 1.4. I'm going to retest with the higher Vfsb and start lowering Vdimm to see where the bottom is Vdimm. Based on earlier testing with mutiple setups it seems the RAM likes Vdimm 1.95v (least # of memtest errors per unit of time).


What I think gets folks into trouble with the 680i is that auto voltage settings. If you don't overclock they stay low (FSB 1.2v, SPP 1.2v) but if you up FSB speed a bit then the auto voltage will bump several voltages up automagically. My mistake was not being careful enough to notice what voltage I was using during what tests I was running.


Ramguy, as noted this solved my problem. Couple follow-up questions if you don't mind.


At Vdimm 2.1v and Vfsb 1.4v the RAM gets hot. Should I be worried or is this expected?


What causes more heat - increased Vdimm or increased Vfsb?


Any concerns about running 4gigs of this RAM on 680i at these settings (Vdimm 2.1, Vfsb 1.4, 800 4-4-4-12)?

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FWIW, I went back and looked at the settings on the 975 and 965 motherboards that we tested this memory on. They had low FSB settings too. My guess is that the RAM we determined as bad probably wasn't bad at all and just needed some +FSB voltage too.
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Increased VFSB shouldn't increase heat too much in the case if you have any kind of case flow.


I guess you should post every setting you are using, and also any kind of multimeter measurements.


SLI-READY memory is bugged on 680i. It may or may not set the voltage correctly depending on what bios you are using.


A lot of the problems you are seeing with these 680i boards is the people are simply not familiar with a board that is quite this complex. It is not your usual plug stuff in and it works right out of the shoot.


I will try to write a guide if I ever have any time again.


Having setup 10 or so 680i boards with Corsair ram in the last 2 months and not having one fail, my guess is that it is not wholly related to ram.


MCP == 1.35-1.4v

SPP == 1.55v (only on high fsb, otherwise nvatabus will crash windows many times, look in system manager)

vFSB = 1.35v-1.4v

VTT = 1.35-1.4v

vMEM = 2.1v

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I have this RAM with a 680i based Asus P5N32-E SLI


First, this board killed 2 of my 4 sticks on the first boot (assuming they did not come from the factory dead). I sent the dead sticks back and have had a hell of a time getting the system stable. I was reluctant to blame the RAM at first because I was running Vista 64-bit and an 8800GTX for which the nVidia drivers are steaming pile of dog sh!t. After playing with the BIOS for a bit I was able to get the system stable in Windows but anytime I played Vanguard:SOH I would get constant system reboots, BSoD, freezes, etc...


I'm not overclocking and CPU, MB and GPU always were well within normal temp. I started on 0602 BIOS but am up to 0702 now and was still having issues when running Vanguard. What made it harder to troubleshoot was that I could run the CPU at 100% and pound on the GPU with all kinds of stress tests and nothing seemed to crash the system but Vanguard. I then ran MemTest86 for 14 hours without errors.


I finally gave up on Vista assuming t was a driver issue but still had problems with Vanguard on XP. I was convinced this was a software issue but I was seeing tons of reboots rather than BSoD or app crashes so I decided to head back into the BIOS.


I was running typically config for this RAM 4-4-4-12-2T @ 2.1v 800Mhz but I decided to lower down to 667Mhz. I've been in Vanguard for over 90 minutes now without an issue. Which is over 90 minutes longer than I could stay in at 800Mhz.


I know Asus has just release 0902 beta BIOS and when I find my damn USB memory key I'll upgrade as it's supposed to be a more stable BIOS.


When my replacement memory comes back I will be at 4Gb and will want to go back to 800Mhz if I can. I have heard 4 sticks @ 800Mhz is not stable on this board. So my question is: Are my problems related to the RAM, the MB, or a combo of the two? Can someone recommend RAM for this MB or a MB for this RAM and I'll make a choice which is the best solution for my problem. I'm leaning towards replacing the RAM just because I won't have to pull my system apart but I'm not impressed with the stability of other 680i platforms so I may be forced back to an Intel chipset.

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