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~~~~~IMPORTANT SANDYBRIDGE OC INFO: Voltages & OC Guide!!~~~~~

Associate
Joined
20 Jul 2007
Posts
295
Location
Preston
Just got my 2500k and msi P67A-C45 mobo with 8 gig of 1600mhz ram. Never overclocked in my life but think now is a good time to start!

Anyone got any advice on the best way to start? I downloaded cpuid and its currently showing this,

imagegq.png


Is there anyway to make the cpu run at 3.3ghz all the time instead of 1.5ghz when it has nothing to do?
 
Soldato
Joined
8 Oct 2006
Posts
5,699
Location
Midlands
Is there anyway to make the cpu run at 3.3ghz all the time instead of 1.5ghz when it has nothing to do?

I'm not quite sure why you would want to do this. On older chips you had no choice if you wanted to overclock but the SB the fact that you can overclock and still have it idle at such low settings is a godsend for heat and energy consumption as well as prolonging the life of your kit as its running at lower volts more often.
 
OcUK Staff
OP
Joined
17 Oct 2002
Posts
38,253
Location
OcUK HQ
HI there

Right memory at 1.65v seems absolutely fine, still not a single issue with our rig, still going strong in prime.

I think the issue is coming from anyone trying a combination of the following:-

1. High Vcore
2. High frequency memory
3. High Vdimm

I think when your trying to push its just too much for the CPU to deal with voltage wise.

These chips to get the best results shoud ideally be set at:-

1. 1.35-1.40v Vcore for maximum overclock and ideally 1.30v for 24/7 running.
2. Keep memory frequency ideally around 1600MHz and tighten the timings up.
3. Keep memory voltage sub 1.55v
4. Keep chipset/pll at default and BCLK at 100MHz.

I think the above setting will yield 4.6GHz-4.8Ghz happily but with complete stability and a system that run around the 75c mark.
 
Associate
Joined
19 Oct 2002
Posts
1,460
Processor Core Active and Idle Mode DC Voltage and Current Specifications
(Sheet 1 of 2)
Symbol Parameter Min Typ Max Unit Note
1
VID VID Range 0.2500 — 1.5200 V 2

From intel's white paper seems 1.52v is the max safe Vcore?
 
Soldato
Joined
21 Sep 2009
Posts
5,249
Location
London
Gibbo, quick question,

For the purpose of this question, lets say the max vcore is 1.3v

When setting the vcore in bios, say for example to 1.28v, and when booting to OS shows 1.28v in CPUZ, and then, when underload, due to the bios compensating for the vdroop, the voltage rises to 1.32v, is this considered to be over the normal working vcore (1.3v), or should the max vcore, when under load be the max vcore?
 
OcUK Staff
OP
Joined
17 Oct 2002
Posts
38,253
Location
OcUK HQ
Gibbo, quick question,

For the purpose of this question, lets say the max vcore is 1.3v

When setting the vcore in bios, say for example to 1.28v, and when booting to OS shows 1.28v in CPUZ, and then, when underload, due to the bios compensating for the vdroop, the voltage rises to 1.32v, is this considered to be over the normal working vcore (1.3v), or should the max vcore, when under load be the max vcore?

I'd say maximum safe voltage is 1.38-1.42v. Its gonna take a few days to test as were trying to kill a CPU. First step is to see if 1.65v memory volts kills it, if after 48hrs prime its still alive I think we can rule that out.

Next step will be to shove 1.45v through it and clock it to around 5GHz and just leave it going and see if it dies. If it lives, then we can point our finger elsewhere or when its a combination of both high vcore and high vdimm.
 
Soldato
Joined
22 May 2007
Posts
3,194
I'd say maximum safe voltage is 1.38-1.42v. Its gonna take a few days to test as were trying to kill a CPU. First step is to see if 1.65v memory volts kills it, if after 48hrs prime its still alive I think we can rule that out.

Next step will be to shove 1.45v through it and clock it to around 5GHz and just leave it going and see if it dies. If it lives, then we can point our finger elsewhere or when its a combination of both high vcore and high vdimm.

I was a bit worried when I tested my i5-2500k out on stock cooling and it reached 79C where I promptly exited Prime 95... I a bit more relieved now that you have stated 4.6-4.8 should be achievable at about 75C (on decent air) I only went 4C above that. Suffice to say I have ordered an Akasa Venom from your shop and intend to run at around 4ghz which is what the automatic overclock produces.
 
Last edited:
Soldato
Joined
21 Sep 2009
Posts
5,249
Location
London
I'd say maximum safe voltage is 1.38-1.42v. Its gonna take a few days to test as were trying to kill a CPU. First step is to see if 1.65v memory volts kills it, if after 48hrs prime its still alive I think we can rule that out.

Next step will be to shove 1.45v through it and clock it to around 5GHz and just leave it going and see if it dies. If it lives, then we can point our finger elsewhere or when its a combination of both high vcore and high vdimm.

Maybe we should open a competition about what finally kills it?

Answers in the following format

5700mhz, 1.68v cpu vcore, 2.8v ram volts, 115 bclk

:p
 
Soldato
Joined
22 May 2007
Posts
3,194
Maybe we should open a competition about what finally kills it?

Answers in the following format

5700mhz, 1.68v cpu vcore, 2.8v ram volts, 115 bclk

:p

I get ya - a kind of guess how many sweets are in the tin kind of thing but with CPUs good idea - winner gets £ 100 to spend in the shop.
 
Associate
Joined
30 Dec 2010
Posts
190
Location
AG Switzerland
HI there

Right memory at 1.65v seems absolutely fine, still not a single issue with our rig, still going strong in prime.

I think the issue is coming from anyone trying a combination of the following:-

1. High Vcore
2. High frequency memory
3. High Vdimm

I think when your trying to push its just too much for the CPU to deal with voltage wise.

These chips to get the best results shoud ideally be set at:-

1. 1.35-1.40v Vcore for maximum overclock and ideally 1.30v for 24/7 running.
2. Keep memory frequency ideally around 1600MHz and tighten the timings up.
3. Keep memory voltage sub 1.55v
4. Keep chipset/pll at default and BCLK at 100MHz.

I think the above setting will yield 4.6GHz-4.8Ghz happily but with complete stability and a system that run around the 75c mark.


Hey Gibbo

Can you expand a bit on your comment on tightening memory timmings. That the one area of overclocking that I get lost at. I am running a 2600k at 4.2Ghz with everything on stock, mem voltage is 1.5v and so far Prime and games havn't caused any issue. I will clock to 4.6ghz then leave it at that, what should I change these memory timmings to???

Corsair Dominator, 1.65v 2 x 4Gb
CMP8GX3M2A1600C9
CL9 ( 9-9-9-24 )
XMS3 DOMINATOR® with DHX+

Thanks for any advice.
 
Soldato
Joined
8 Oct 2006
Posts
5,699
Location
Midlands
I will clock to 4.6ghz then leave it at that, what should I change these memory timmings to???

Corsair Dominator, 1.65v 2 x 4Gb
CMP8GX3M2A1600C9
CL9 ( 9-9-9-24 )
XMS3 DOMINATOR® with DHX+

Thanks for any advice.

You could try 8-8-8 but i wouldnt worry overly

check out this bit-tech rundown of different ram speeds and latencies on Sandy Bridge. The difference it makes is minimal at best.
 
Soldato
Joined
22 Mar 2009
Posts
5,712
Hi all, I am going to order my i7 2600K and P67 motherboard later this month and I will going to use my own memory ram, my tower case and also noctua d14. I will post back once I had received the cpu processor and the board with overclocking @ 4.2, 4.4, 4.6 and maybe 4.8.
 
Soldato
Joined
22 Mar 2009
Posts
5,712
I'd say maximum safe voltage is 1.38-1.42v. Its gonna take a few days to test as were trying to kill a CPU. First step is to see if 1.65v memory volts kills it, if after 48hrs prime its still alive I think we can rule that out.

Next step will be to shove 1.45v through it and clock it to around 5GHz and just leave it going and see if it dies. If it lives, then we can point our finger elsewhere or when its a combination of both high vcore and high vdimm.

Nice one Gibbo, kept us informed. One way to find out sooner or later. Thanks for let us know.
 
Associate
Joined
20 Feb 2009
Posts
2,052
Location
Rugby
These are just guidelines we recommend you follow, if you want to push more voltage through your CPU's then just be aware they could die on you. Your warranty is un-affected and we will honor any CPU's that die, we just won't ask questions as to how you killed them. ;)

When you say the warranty is un-affected, does that mean Intel don't care if we OC our chips to death? Or is that just the standing of OCUK on the matter? Also, if I purchased a SB build now, and it failed in months/years time due to the OC, would this still be the case, or is it only now due to the high number that is failing?
 
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