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2500k above 4.8

forteh

forteh

forteh

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Joined
18 Jan 2010
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224
Location
Lichfield
Having just picked up a 2500k and p67 sabretooth (yeah I'm behind the times :D) I've been playing with the overclock to see how far I can reliably push it.

It's gone up to 4.8ghz without much hassle with the following settings: -

vcore 1.44/1.45v (under load - 1.425v in bios)
llc extreme
cpu current 140%
vrm frequency 350

After an hour of prime it had peak at 77 with average being high 60s, cooling is a truespirit 140bw without a case, effectively just a motherboard screwed to the wall.

Are there any other settings that I should alter other than push vcore up until I hit my temperature or 1.5v limit? This is the first time playing with sandybridge so not really familiar with it and not sure if I should be increasing something else in addition to vcore?

Beers in advance :D
 
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I've pushed the voltage up to 1.52v (under load) and upped it to 5ghz, it initially failed after a couple of minutes of prime so I've added 0.05v of pll to take it up to 1.85v and it seems to be holding so far (5 minutes in!).

Peak temps so far is 74°C :)

edit: BSOD a couple of minutes afterwards, pushed pll up to 1.9v to see if it helps.
 
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Isn't intels max safe voltage for sandybridge 1.52V?
Either way after benchmarking arma3, 5ghz didn't increase fps over 4.8ghz due to maxing out my gtx660. Running back at 4.8 @ 1.425V, nice to know it will run up to 5ghz on air :)
 
Mine needs 1.425 to hit 4.8, anything less and it's not stable. Are there any settings that might allow me to reduce vcore?
 
forteh said:
Mine needs 1.425 to hit 4.8, anything less and it's not stable. Are there any settings that might allow me to reduce vcore?
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because you are running it under water you can probably get away with running 1.425v. i ran my 2550K on 1.4v@5ghz for a year on air cooling and it was ok. people running them under water at 1.5v found that they degrade or die with 1-3 years.
 
I'm on air, thermalright truespirit 140bw :)
How do I go about finding the default voltage in order to work out using offset voltage? I tried running it with voltage on auto offset and it pinged it up to 1.6v. I tried setting a minus offset of 0.2v to bring it back to the 1.4 range and it won't post :(
 
forteh said:
I'm on air, thermalright truespirit 140bw :)
How do I go about finding the default voltage in order to work out using offset voltage? I tried running it with voltage on auto offset and it pinged it up to 1.6v. I tried setting a minus offset of 0.2v to bring it back to the 1.4 range and it won't post :(
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minus offset of 0.2v would give you around 0.9v.

Dont use offset just set the vcore, start at 1.425 and see when you max multi is. dont go over 1.425
 
Setting it at 1.425 in bios gives me 1.425-1.45 under load @ 4.8, I'll test now to see if I can hit 4.9 with 1.425.

I've just tried clocking it back to 4.6 @ 1.4v in bios and it's peaked at 1.456v after about 20 minutes of prime although generally the vcore is lower; obviously this is the llc doing its job.

edit: nope didn't like [email protected], now testing [email protected] and it's done 10 minutes without a hitch so far; will conduct further stress testing later. Does pushing the bclk take as much voltage as increasing the multiplier? It's needing a big chunk of voltage to push from 4.7 to 4.8 ghz so perhaps putting 2-3mhz on the bclk will achieve the same result for less voltage cost?
 
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Mine too needs a big increase to go from 4.7 to 4.8, it's stable at 1.39 for 4.7 and temps are great so that's where I settled. Out of interest no matter what I do it won't post at anything over 4.8.
 
You can disable a couple of cores and maybe get a little higher.

Which would be fine for anything that does not need more than 2 threads...

Mine won't go past 4.8 on anything other than 2 or less cores.
 
Wound it back to [email protected] and it appears short term stable with an hour of prime. Vcore has peaked at 1.44v with 1.408-1.416 being typical. Temperatures have peaked at 66/71/74/69°C and typical temps when not running small FFTs is 55/57/60/57°C so no issues with temperature :D

It will run 4.8 quite happily, just needs a big bump to get there, it will also run 5 but voltages are higher than I would like them to be. Cheers for all the advice so far :)
 
forteh said:
Wound it back to [email protected] and it appears short term stable with an hour of prime. Vcore has peaked at 1.44v with 1.408-1.416 being typical. Temperatures have peaked at 66/71/74/69°C and typical temps when not running small FFTs is 55/57/60/57°C so no issues with temperature :D

It will run 4.8 quite happily, just needs a big bump to get there, it will also run 5 but voltages are higher than I would like them to be. Cheers for all the advice so far :)
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I dont want to make mine past 1.45v as its unknown teritory for me, i mean, currently, holding a stable overclock of 5.00Ghz at 1.44v, with prime running for half an hour, temps are deffo not an issue, mid 40's to low 50's.

you get some good 2500K processors and some bad for overclocking....
 
Well mine will certainly hit 5ghz, possibly more. I didn't do any tuning of voltage to achieve 5, I just whacked vcore up to 1.5v to see if it will do it (I read that 1.52 is safe limit but peoples general opinion in here is it's better lower); it may well hit 5 with 1.45v.

For my usage though 4.8 pretty much maxes out my gpu in arma3 and 4.7 runs about 1 fps slower but at a much lower voltage which is a safer bet for me :)
 
For a couple of days now I've left it running prime whilst I'm at work, it seems to last about 6 - 7 hours before bsod with a 124, temperatures aren't getting over 71℃ with an offset of -0.040v . It's fully stable so far for other uses but would you consider 6 hours prime to be reasonable?
 
forteh said:
For a couple of days now I've left it running prime whilst I'm at work, it seems to last about 6 - 7 hours before bsod with a 124, temperatures aren't getting over 71℃ with an offset of -0.040v . It's fully stable so far for other uses but would you consider 6 hours prime to be reasonable?
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6 hours should be fine, but 124 means you will need to add more volts if it bosd often.
 
Completed a 10 hour prime blend today @ 4.7 without a hitch :)
Using -0.025 offset, extreme llc and dropping the pll down to 1.6v (1.8v stock), highest temp is 75℃ on one core with the rest around the high 60s. I think I've got bad paste application because there is quite a variance in the core temps.

Now I'm running on offset voltage I might see what happens at 5ghz, @4.7 voltage spiked up to 1.456 but it's typically below 1.43v.

Does sandybridge normally need much extra vram / imc voltage to tighten up memory timings?
 
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