Sandy Bridge max voltage *warning*

sirmonkey1985

[H]ard|DCer of the Month - July 2010
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Sep 13, 2008
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saw this thread on forums.overclockers.co.uk might be worth your time to follow.


Gibbo said:
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.
wink.gif


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

its almost posted on overclocker.net

http://www.overclock.net/intel-cpus/911402-sandybridge-take-note.html

just thought i'd forward this on. if it was already posted and i missed the thread just let me know and i'll close it or the mod's can.
 

GoldenTiger

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Dec 2, 2004
Messages
26,006
As I posted in another thread on this...

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http://www.xtremesystems.org/forums/showpost.php?p=4699227&postcount=156
Voltages:
Now let’s move to voltages, this is very important and I think anyone looking to overclock should have a thorough introduction to the variety of voltages that the user is able to control.
Make sure to pay attention to my tid-bits on Vcore(VCC) and VTT(VCCIO), these are most important for overclocking, other voltages can help too.

Here is a table I put together from Intel’s product data sheet; it defines the processors maximum voltages and maximum amperage- These are OFFICIAL Min and Max Values:

(PICTURE SNIPPED)

VCC: Commonly Called Vcore, the voltage supplied to the processors inside the CPU. This voltage is a large part of Sandy Bridge overclocking. Now from personal testing, and weeks and weeks of headaches and hard ships, I have a few things I would like to share about this voltage.
I say maximum voltage for Vcc/Vcore is 1.50v for 24/7, 1.55-1.60v for extreme benchmarking, please stay below to 1.6, and don’t use any type of Load Line Calibration past 1.55v. Please not that high temperature teamed up with high voltage will kill your processor faster than anything else, it creates a perfect environment for processor degradation.

That's a lot more reliable to me than some random review site parroting Intel pr :). Guy knows his stuff from what I've seen in the past.
 

gunderwood

Weaksauce
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Sep 25, 2006
Messages
111
However, read the notes:

1. Unless otherwise noted, all specifications in this table are based on estimates and simulations or empirical
data. These specifications will be updated with characterized data from silicon measurements at a later
date.

2. Each processor is programmed with a maximum valid voltage identification value (VID) that is set at
manufacturing and cannot be altered. Individual maximum VID values are calibrated during manufacturing
such that two processors at the same frequency may have different settings within the VID range. Note
that this differs from the VID employed by the processor during a power management event (Adaptive
Thermal Monitor, Enhanced Intel SpeedStep Technology, or Low Power States).

I'm guessing that Intel changed how they spec VID and the max VID is no longer lower than the max safe 24/7 voltage. It makes sense to define a spec which covers the whole range of possible VIDs needed and design to that. If you look at Table 7-1 (found here http://download.intel.com/design/processor/datashts/324641.pdf) they use an 8-bit VID with zero being 0V and 1 being 0.25V with small but regular increases to FF (hex) which is 1.52V.

I don't think Intel was intending to ship processors with a VID of FF or 1.52V. I think they started at 0.25V for the spec and just kept defining it until they hit 1.52V. When they created the spec I doubt they knew 100% if 1.52V would be safe or not for SB/32nm.

It's a design to spec intended to cover a wider range than is thought neccessary, not a definition of what is safe IMHO.
 

Blahman

[H]ard|Gawd
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Messages
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Lol, this shit is all over the board, first guy says 1.38 max, second guy says 1.5. I think it's safe to say you can take anything anyone says about this with a grain of salt if they don't provide empirical data.

Personally I have had zero issues running 4.8GHz at 1.48V load (1.0V idle) 24/7. My temps idle around 30C and max out at 70C. If the voltage was high enough to do damage I think the temps would be higher.
 
Joined
Nov 6, 2008
Messages
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Based on ridiculous amounts of research, I agree mostly with this, but wouldn't really recommend anything over 1.46v myself:

I say maximum voltage for Vcc/Vcore is 1.50v for 24/7, 1.55-1.60v for extreme benchmarking, please stay below to 1.6, and don’t use any type of Load Line Calibration past 1.55v. Please not that high temperature teamed up with high voltage will kill your processor faster than anything else, it creates a perfect environment for processor degradation.

BCLK overclocking is recommended against on SB for obvious reasons, but you can definitely safely go up a little bit. Because this affects CPU, RAM, and PCIE, you can't go much beyond 110 without stability becoming a major worry. Nvidia cards are more finicky than ATI, so 110 is likely more stable with ATI cards. When I had that GTX 275, it wouldn't let me OC the PCIE bus beyond 104 without freaking out pretty bad (driver crashes were rampant at 105). RAM is the secondary concern here, since stupid-cheap RAM is likely to not be very overclockable. The CPU is really the least of your worries for this, the major thing about the CPU is to remember that SB uses high multipliers so even a few MhZ up on the BCLK can be a pretty big speed boost.

My 24/7 OC is only a hair above 4GhZ @ 103x39, but the highest I've taken this 2600K is 99x51 (5.05GhZ). Both are ridiculously stable, but I don't do enough heavy stuff daily to justify anything over 4GhZ. If I want to game, I load a profile that is 105x42 for 4.4GhZ. All 3 of these speeds are perfectly stable.
 

tangoseal

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Dec 18, 2010
Messages
9,417
LOL... that is recommended from a business that builds gaming PCs obviously. They are recommending you do not try and up the voltage because they dont want to deal with the warranty.

This is not even thread worthy honestly since it is from a business trying to make money and prevent warranty claims by being over the top safe with their recommendations.

This is no different than someone telling you not to drive your car past 55mph in a 65mph speed zone so you WILL NEVER get a ticket.

I have already addressed this as well as others:

http://hardforum.com/showthread.php?t=1578688&highlight=Sandy+Bridge+Max+Voltage
 
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