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

[Gibbo]

Hi there


Right guys myself and our technical guys have spent the entire weekend and this morning in discussions with Intel regarding the alarming amount of reports of Sandybridge CPU's dying and have been conducting our own testing as have Intel to find out what is a definite no no.


Sandybridge maximum safe voltages

Core Voltage - Not recommended too exceed 1.38v, doing so could kill the CPU, we therefor recommend a range of 1.325-1.350v if overclocking.
Memory Voltage - Intel recommend 1.50v plus/minus 5% which means upto 1.58v is the safe recommended limit. In our testing we have found 1.65v has caused no issues.
BCLK Base Clock - This is strictly a NO, anyone using base clock overclocking could/will cause damange to CPU/Mainboard. (Set manually to 100)
PLL Voltage - Do not exceed 1.9v!!



Processor - Basically we recommend customers not to exceed 1.35v to play it safe, all our bundles are set at 1.3250v or lower, any competitors offering bundles above 4.6GHz you should be enquiring as to what voltage they are using as we believe anything over 1.38v will limit CPU lifespan and anything over 1.42v will likely kill the CPU or severely limit its lifespan.

Memory - Intel recommend 1.50v plus/minus 5% which means 1.60v is the ideal safe maximum, but we have found in our testing all 1.65v memory is fine. We have also found most new 1.65v like Corsair XMS3 will run at its rated timings with just 1.50-1.55v which is well within Intel specifications. So people upgrading to Sandybridge you can still use your old DDR3, but we do recommend you run it at 1.60v or less. We are shipping most of our bundles which feature Corsair XMS at 1.50v-1.55v at rated timings. We've also discussed with Asus and MSI regarding voltages for memory and they also confirm in their testing 1.65v caused no issues with reliability.

Base Clock - To put it simple if you value the life of your components, do not overclock using base clock!

PLL Voltage - Again do not exceed 1.9v!


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.

Not all CPU's are as fragile as others, we have experimented upto 1.50v Vcore and 1.70v memory and had zero issues with reliability, so it seems some of fine when pushing hard.

 

[Gibbo]

Wonder why baseclock changed so much for this series

Possibly the onboard graphics?

 

[Gibbo]

Why do I now have a feeling that we are now about to see a 'new' range of higher priced 'Sandy Bridge compatible' lower voltage memory modules 'launched' by all the major manufacturers!

We have a brand new range en-route, pricing not much higher but it should be higher as the current DDR3 has got way too cheap, might as well be giving it away.

 

[Gibbo]

Hi there

The XMS3 however is proving excellent in our testing today, so far stable at 1.40v at rated timings (1600MHz 9-9-9-24).

 

[Gibbo]

I just notice other company had now reduced the overclock speed from 4.8GHz to 4.6GHz on both i5 2500K and i7 2600K now. Hmmm very interesting really. Look like they been in touch with Intel directly just like what OCUK did. But, OCUK did a sensible in the 1st place with all bundles at 4.6Ghz. Well done ocuk.

Well we have had stock longer, more time to conduct proper testing and we feel 4.6GHz is a good reliable overclock that we can sell and give with a confidence a full warranty.

Our test rig here is running like a gem, prime stable, memtest stable and that is at 4.2GHz from a 2500k in a Asus Pro P67 board at stock voltage. The cooler is an Akasa Venom. The memory XMS3 is running at 1600MHz at just 1.40v completely memtest stable, infact we feel the memory will be fine at just 1.35v too.

All in all its very impressive they can do 4.2GHz at stock volts and Corsair's 1.65v rated memory run at its rated timings as low as 1.35v prime stable. All round very pleased. Gonna leave it priming overnight with memory set to 1.65v just to see if it dies.

 

[Gibbo]

Someone on another forum has got to 4.8ghz stable at 1.33vcore !!!

http://img207.imageshack.us/img207/4213/91166230.png

Well our test rig at 4.2GHz is sitting around 1.2v, we shall see what she can reach at 1.3v tomorrow.

 

[Gibbo]

Anyone tried the Geil value kits running less than their stated 1.6v?

Yep the GeIL seems happy as low as 1.45v, but so far Corsair XMS3 is leading the way with working fine as low as 1.35v.

I think GeIL and XMS3 are the best value bets as they will quite happily run at rated timings with 1.50-1.55v which is within Intel specs.

Some very lucky people will get memory that runs even lower voltages.

 

[Gibbo]

Just an update on this. I've now got it running at a voltage of 1.5 with a reduced effective speed of 1333Mhz but tighter timings. I have run benchmarks of the main games I play and it actually runs about the same (in some instances slightly quicker) so I think I will leave it as I am more comfortable with 1.5 volts. It also seems stable at 4.4Ghz with the same VCORE, incidentally. I am liking the efficiency.

I've always found tighter timings give a better real world improvement over outright speed with memory.

For me the best performance comes from finding a kit that will run at 1600MHz with 6-7-6-20 timings, though there is very little RAM out there that can do that these days, especially at sub 1.60v.

Though I shall be adding a whole new range of 1.50v to the site middle of this week that is very nice and also getting some new Corsair Vengeance lines in as well which will be perfect for Sandybridge.

 

[Gibbo]

Just started to OC.

What sort of max temps should I expect. At 4Ghz, mem at 1.5v, CPU voltage not touched, running prime95 I have 68deg C max after 10 mins.

Is that ok?? H70 cooler btw.

Our rig on an open bench was using an Akasa Venom at lowest fan speed and at 4.2GHz after 5hrs it was 62c.

 

[Gibbo]

have just got mine up and running an into windows, (2500k, XMS3 Asus PRO), and it has auto set my BCLK to 100.3 MHz, should I go into bios and set it manually to 100 exactly, or is this small a nudge acceptable?
also, I have no Idea what voltage it has chosen for my memory, but its at 669(x2) MHz, so about 1333 DDR. Jdec for 1333 is 1.5v, so i guess its this, but what software can I use to check?
gonna have a look in bios in the next couple of days, set mem at 1600 (I'll try 1.4v, cheers Gibbo!), so I will prob set the BCLK to 100 then.

Trojan.

sidenote: didn't recieve my copy of lost planet 2 either, I'll call you (OcUK) about that one tomorrow!

Hi there

Manually set BCLK to 100MHz.

Set your memory to 1600MHz and set the voltage to 1.50v

 

[Gibbo]

reminds me of the northwood sudden death syndrome.

My 1.6 Northwood ran at 3.2+ for months before it electromigrated, but I was giving it some serious voltage and it did run SETI 24/7

 

[Gibbo]

Mine auto overclocks to 103 * 39 or 4ghz and it dishes out 1.240v vcore in the process... I guess some can auto overclock to 4.3 and others only to 4.0ghz

Its better to do it manually and set BCLK too 100MHz and then use the multiplier to overclock.

 

[Gibbo]

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.

 

[Gibbo]

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.

 

[Gibbo]

Ok, lets go for 4.6 as a start

In your Bios, set your multi to 46

then

VCCORE 1.28
IO 1.048
SA 0.945
CPUPLL 1.88

Then post up a cpuz

CPUPLL just be careful of that one mate, stock is 1.80v and sandybridge boards seem rather sensitive to upping volts on PLL, it may just be bios issues, but I'd leave PLL at stock.

 

[Gibbo]

I was welcomed to a blue screen before windows loaded. Everything is back to auto now except multi at 42, BCLK 100.

Voltage seems high for only 4.2Ghz.

If thats an Asus board, voltage seems right, ours is same at 4.2GHz.

 

[Gibbo]

Yes it is the P8P67 Pro. That's reassuring!

Current priming 4.4Ghz at 1.32V

Ours has been under constant prime now for nearly 72hrs, without issue.

 

[Gibbo]

Our is still running Prime with memory at 1.65v, still no issues, shall give it until end of day and then move to clocking the hell out of CPU, but I think we can assume running memory at 1.65v does not kill these, its just not recommended.

 

[Gibbo]

Hi there

Our test rig did over 48hrs and 1.65v memory prime stable, no issues. So memory voltage is not harming this one.

Were now running 4.8GHz with 1.45v, so a lot of voltage, so far 6hrs stable, so lets see how it fares.

 

[Gibbo]

What's happened to OcUK overclocked bundles, suddenly you are selling them overclocked to 4.4ghz only down from 4.6ghz, just about when I was going to make a purchase ie

"Radon Allosaur" Intel Core i5 2500K 3.30GHz @ 4.40GHz Overclocked Bundle - Asus

They are doing further testing, as some bundles are just hitting a wall beyond 4.4GHz irrelevent of voltages used which could mean some CPU's hit a wall at certain speeds or its something else holding back. As such bundles will be 4.40GHz from now on.