Best voltages to achieve a overclock on E8400

PITTBULL

Junior Member
Aug 27, 2008
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wanting to come here and ask and see what the best Voltages on a

-EVGA 680i SE Mother board

-E8400 Core 2 stock @ 3.00 ghz

to achieve a clock around 3.60 and see how safe it is to push this processor on my board



i have 2x1gb OCZ Reaper memory @ 1150 mhz on 2.0 volts

i have my processor clocked @ 3.60 right now with with all voltage settings below


Core @ 1.375 volts
FSB @ 1.4 volts
nforce SPP @ 1.5 volts
nforce MCP @ 1.5 volts
nforce SPP-MCP @ 1.25 volts
 

scruffypup

Senior member
Feb 3, 2006
371
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There is no "best" as every single build will vary some. Two people may have the exact same components and have different voltages to achieve stability. Start off with stock voltages and read the how to guide listed in the forum if you have no clue on how to overclock.

If you are not wanting to do the work, stay at stock voltages and see if it works. If not, well,... back to doing the work.
 

BonzaiDuck

Lifer
Jun 30, 2004
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My 680i board may not require the same voltage settings as your eVGA board, but I have noticed that for this chipset, they are understandably close. Maybe you can achieve the 3.6Ghz target with an "Auto" Vcore setting -- maybe not. I can't. Further, I had to adjust the CPU_VTT voltage to 1.45V (BIOS monitor reports the sensor reading of 1.39V). This is the limit mentioned in a brief comment by Anandtech "techs" noting that a VTT voltage that is too high will kill your Wolfdale very soon. That is, according to the Anandtech article, the actual voltage should not much exceed 1.45V, and that 1.5V or higher will profoundly increase risk of short processor longevity. And it had been shown with the earlier 65nm Conroe processors (C2D and C2Q) that you definitely had to bump up the CPU_VTT voltage as you move toward and past a CPU_FSB speed of 400 Mhz. 400 Mhz is exactly what you need to get 3.60Ghz, or multiplier-9 x 400 = 3600 Mhz.

But with my ASUS Striker Extreme 680i, I had to manually adjust the vCore voltage, which is currently set at 1.32+V. My setting was chosen as that which provided rock-stable Blend Testing with PRIME95 for about 14 hours -- at a speed of precisely 3.645 Ghz. This setting was 5 Mhz higher than the CPU_FSB value of 400 Mhz needed to obtain 3.60 Ghz (or 9 x 400) with the E8400 processor.

Anyone may differ, or say that I'm offering snake-oil here, but you'd probably want to look at the thread started early this year asking people to post their results with the Wolfdale processors. That will give you a ballpark estimate of vCore settings across a range of motherboards, and you can narrow down the range to "all 680i motherboards," and even to the eVGA.

Keep in mind, though, that different BIOS revisions may change slightly the "set" voltage you choose in the BIOS menus to get the processor and board to run stable at that speed. There is always a discrepancy between the BIOS monitor reading of the sensor, and I think it is a safe bet that the discrepancy varies with BIOS revision and board manufacture, even if a 680i chipset is common between boards, or a 680i reference design is common between them.

The thread in question may provide a good guideline, keeping in mind that some people may exaggerate their results, fail to stress-test for a significant length of time, or fail to set the vCore to a minimum necessary to achieve stability.
 

PITTBULL

Junior Member
Aug 27, 2008
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well my V Core idles back and forth around 1.30 to 1.31 because of V droop, me and my buddy felt it would be safe to bump all other voltages up one notch i can back those back down if you guys think its neccesary

i had a E6300 @ 2.54 ghz beforehand with normal temps 38 to 43 C* idle to ingame

with this E8400 @ 3.60 im getting temps from idle @ 40 C* to in game temps up to 49 C* thats the highest ive seen

my CPUZ stats

http://dow-stats.com/modules/N4G-SigHost/images/sigs/cpu.jpg
 

BonzaiDuck

Lifer
Jun 30, 2004
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Originally posted by: PITTBULL
well my V Core idles back and forth around 1.30 to 1.31 because of V droop, me and my buddy felt it would be safe to bump all other voltages up one notch i can back those back down if you guys think its neccesary

i had a E6300 @ 2.54 ghz beforehand with normal temps 38 to 43 C* idle to ingame

with this E8400 @ 3.60 im getting temps from idle @ 40 C* to in game temps up to 49 C* thats the highest ive seen

my CPUZ stats

http://dow-stats.com/modules/N4G-SigHost/images/sigs/cpu.jpg

I think you're talking about something else here. vDroop occurs under load -- or the difference between idle and load voltage.

If you are "set" at 1.37V and you get that sensor reading of 1.31-something, I don't know what to tell you to do. This was a problem with earlier BIOS revisions of my Striker Extreme 680i board -- corrected in subsequent revisions. I'd probably say first, "find the latest BIOS update, reset the CMOS after turning off and unplugging the system, re-flash the BIOS with the latest update, and see if the reading more properly reflects the 'set' value.'"

On my own system, if I bump up the VCORE to 1.33 or 1.34, it will still show an idle value of 1.31 to 1.32. I have to keep bumping up higher to get the reading to respond. At 1.31+, it would show 1.29V, and at 1.32+ it would show 1.31V at idle. Maybe I should have tempered my remarks in my previous post to mention that. I had said "1.32+" which was my "set" value.

This is tricky business if the "set" value doesn't match the sensor reading, and especially if the sensor reading doesn't match the "real" voltage.

EDIT: On the temperature angle, and on my 680i board - and possibly 680i generally -- this has also been a BIOS-revision issue as the Wolfdale processors began appearing on the market in January of this year. With one earlier BIOS revision, my idle showed 10C CPU temperature, and the next most recent BIOS revision showed 50C. For this processor at commonly experienced room-ambients (say, 75F degrees) these processors should probably be showing temperatures not that far above the room -ambient.

When I updated my BIOS to the revision just posted three weeks ago, it seemed to have "reasonable temperatures." But if it shows idle of 40C and game play pushes it only 9C degrees, that's an indicator of something that should be of comfort to you.

Get RealTemp and run the test to see if the sensors are functioning properly. And also, RealTemp is the most trusted software for reading the sensors in Windows from these processors -- the Wolfdales and more generally Penryn models.
 

PITTBULL

Junior Member
Aug 27, 2008
8
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cool nice program thanks for sharing, on the real temps temp i get 30 and 34 C* reading on idle i think im going to push it to 4.0 ghz and see how stable it is there
 

BonzaiDuck

Lifer
Jun 30, 2004
16,127
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Running only PRIME95 small-FFTs, I had it stable (under only that test) at 3.82 and around 1.37V Vcore.

There are a lot folks here whom I respect, who are more daring in "hanging their a__ over the edge to push the outside of that envelope." [The Right Stuff].

For the moment, I have retired to the base-camp of 3.6 Ghz -- validated rock-steady at 3.645Ghz -- to rest and re-group before attempting another ascent on the K2 and Everest of over-clocking.

Despite the ambivalence of users who seem split down the middle in their opinion of the board, my Striker Extreme had some kudos from serious benchtesting sites. Others here had eVGA or similar boards, and their experience and remarks with both STriker and eVGA seemed to confirm that the 680i has some limitations.

In my own judgment for dealing with a B3 Q6600 using the same motherboard, I am of the cautious opinion that the threshold where 1.2V_HT and CPU_VTT need to be adjusted to the range of a safe limit is an indicator that an upper limit or exponentially increasing VCORE requirement is "nearby."

But, like I said, I'm chilling out at base-camp, and may try it some more myself. I hope you can get there without any . . . . panic-precipitating setbacks.

Let me know how it goes. I'll be very interested.
 

PITTBULL

Junior Member
Aug 27, 2008
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well my buddy has already got it on 4.0 ghz with no issues on the 780i board with a core voltage of 1.42 v

1 degree C* change as mine runs somewhat hotter need new fans thru-out my case
 

BonzaiDuck

Lifer
Jun 30, 2004
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Pretty good!! Your friend's voltage -- set, CPU-Z or otherwise -- might worry me a tad.

The more I think of it, if I'm planning to save a little chump change while watching prices for that E0 E8600, I could probably risk killing the E8400.

I'm pretty sure of one thing: if you "got there" -- and even if you haven't validated with a half-day's PRIME-ing -- it should be do-able for me.

I'd be interested what IntelBurnTest shows under that clock setting, though. But go figure -- it's a 33% over-clock. That was still easy for a Conroe, and would seem even easier for a Penryn.
 

PITTBULL

Junior Member
Aug 27, 2008
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i been playing BF2 for hours on end sinc3e OCing and no issue my temps are around 54 C* with 2 fans out right now so im sure ill be in mid to low 40s once my new fans get here
 

BonzaiDuck

Lifer
Jun 30, 2004
16,127
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Can you accurately measure your room-ambient temperature? If you're gaming and the core temps are only around 54C, that really looks rather promising.

 

PITTBULL

Junior Member
Aug 27, 2008
8
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its pretty hot in my room i live in a built in garage the room is higher therefore it stays warmer in here
 

PITTBULL

Junior Member
Aug 27, 2008
8
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also i have 2 fans out in my tower, my buddy is running cooler on the 780i @ 49 C* in game max
 

mrfatboy

Senior member
Sep 3, 2006
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Stop playing BF2 and being a claywhore and overclock that baby :) Maybe you can cook some eggs on that thing :)

cya manana :)


 

OCChronic

Member
May 7, 2008
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I lke to set the CPU voltage to the max of the INTEL SPEC range. An E8400 'CO' revision max. is at 1.3625 volts. Any more on my E8400 actually doesn't improve OC'ing much at all. I can net a 3.8Ghz OC, rock stable at this VCore.
 

BonzaiDuck

Lifer
Jun 30, 2004
16,127
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Originally posted by: OCChronic
I lke to set the CPU voltage to the max of the INTEL SPEC range. An E8400 'CO' revision max. is at 1.3625 volts. Any more on my E8400 actually doesn't improve OC'ing much at all. I can net a 3.8Ghz OC, rock stable at this VCore.

I've continued to be cautious about this, choosing "red-line" paramaters on voltage such as those you cite here. As I said, the general wisdom says "1.4V" means that you take responsibility for the risk -- at least to the processor. Then, there is the discrepancy between "set" and "real-time, monitored," and the issue as to whether the "real" voltage is somewhere in that vicinity.

With my motherboard and chipset, the early BIOS' of late 2006 showed such a discrepancy that pushing the VCORE setting to 1.5V would leave it below a "monitored" value of 1.4.

And what you cite as a 3.8 OC with around 1.3625 Vcore "set" is about where I tentatively had my system -- I think it was 3.82Ghz. I might have tried to get this setting totally stable with a few more tweaks, and may go back to it within the next couple days.

Ultimately -- and not questioning PITBULL's thoroughness -- it boils down to the final stability testing. If you look at the results people had posted at the beginning of the year, I think one would find a few that are suspect-- for only having been PRIME'd for an hour or two -- even if they didn't say so.
 

john3850

Golden Member
Oct 19, 2002
1,436
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Originally posted by: BonzaiDuck
Originally posted by: OCChronic
I lke to set the CPU voltage to the max of the INTEL SPEC range. An E8400 'CO' revision max. is at 1.3625 volts. Any more on my E8400 actually doesn't improve OC'ing much at all. I can net a 3.8Ghz OC, rock stable at this VCore.

I've continued to be cautious about this, choosing "red-line" paramaters on voltage such as those you cite here. As I said, the general wisdom says "1.4V" means that you take responsibility for the risk -- at least to the processor. Then, there is the discrepancy between "set" and "real-time, monitored," and the issue as to whether the "real" voltage is somewhere in that vicinity.

With my motherboard and chipset, the early BIOS' of late 2006 showed such a discrepancy that pushing the VCORE setting to 1.5V would leave it below a "monitored" value of 1.4.

And what you cite as a 3.8 OC with around 1.3625 Vcore "set" is about where I tentatively had my system -- I think it was 3.82Ghz. I might have tried to get this setting totally stable with a few more tweaks, and may go back to it within the next couple days.

Ultimately -- and not questioning PITBULL's thoroughness -- it boils down to the final stability testing. If you look at the results people had posted at the beginning of the year, I think one would find a few that are suspect-- for only having been PRIME'd for an hour or two -- even if they didn't say so.