i5/i7 Lynnfield QPI/VTT voltage

[aigomorla]

now i understand why u guys all cry about higher voltages on LGA1156

You can cheat vcore by raising Vtt.

Usually a good solid overclock of around 4ghz on a 920 will be like 1.275 - 1.325 because were using about 1.2875-1.325Vtt

if u guys have a really neutered vtt of 1.21, you would need to compensate via vcore.
And if u pump too much vcore your socket blows out unless your on the lote sockets.

wow... sorry guys.. i really feel for ya... intel fubared this up for long term overclocking.

 

[BababooeyHTJ]

now i understand why u guys all cry about higher voltages on LGA1156

You can cheat vcore by raising Vtt.

Usually a good solid overclock of around 4ghz on a 920 will be like 1.275 - 1.325 because were using about 1.2875-1.325Vtt

if u guys have a really neutered vtt of 1.21, you would need to compensate via vcore.
And if u pump too much vcore your socket blows out unless your on the lote sockets.

wow... sorry guys.. i really feel for ya... intel fubared this up for long term overclocking.

Actually those burnt up sockets are usually burnt up on the vtt pins, afaik. Makes me wonder if the low max vtt has anything to do with that.

 

[DrMrLordX]

wow... sorry guys.. i really feel for ya... intel fubared this up for long term overclocking.

Seems like a lot of guys have popped Clarksdales over at XS where they are fighting for high BCLK to offset the memory controller problems endemic to those chips. Typically they are running vtt pretty high on H55/57/P55 which may be what makes Clarkbar asplode. Of course, they are running a lot of voltages high over there so . . .

 

[aigomorla]

yeah but 1.21vtt is piss change.

even yorkfields had a tollerance of up to 1.375 for long term use.

 

[Rubycon]

MAX VTT on an LGA1156 is 1.21v?

That's like someone grabbing you by the B@LLs in overclocking.

The singer of Yes must have overclocked his nuts off!

 

[BababooeyHTJ]

I would love to know why exactly these chips supposedly can handle so much less vtt than 1366. What exactly is different about the mch and qpi?

 

[ehume]

MAX VTT on an LGA1156 is 1.21v?

You guys kidding me right?

That's like someone grabbing you by the B@LLs in overclocking.

Now i see why u guys need a Ton of Vcore.

OMG... thats so sad... higher bclk will demand a higher Vtt.

Rub, rub, rub, rub it in.

I've been running my Vtt at 1.19v. I think I'll try that 1.155v number and see if the thing is still stable. It did a 12 hour run on OCCT/Linpack with Vcore set to 1.31250v and actually running at 1.328v (LLC and HT on). I try to keep the temps down so my air cooling won't sound like the Ninth Circle of Hell from the cpu fans wailing. The only way it will work with these numbers is to keep bclk down at 182. I wish the 860 had an unlocked multiplier so I wouldn't need Turbo Boost to get to 4GHz.

Oh, the sad trade-offs.

 

[RussianSensation]

now i understand why u guys all cry about higher voltages on LGA1156

You can cheat vcore by raising Vtt.

Usually a good solid overclock of around 4ghz on a 920 will be like 1.275 - 1.325 because were using about 1.2875-1.325Vtt

if u guys have a really neutered vtt of 1.21, you would need to compensate via vcore.

Ya exactly

I am pretty sure I'd rather run Vtt of 1.25V (which is only 3.3% higher than maximum recommended) and VCore of 1.312V vs. 1.408V which is 7.3% higher, and bound to shoot up your temps into the 80s. I am constantly amazed that you can push an Intel processor really far, but my friends are now on their 3rd-4th Xbox360. Quality control !

 

[EarthwormJim]

My core i7 860 died on me last night. I had it running at 1.3v Vtt measured by HW monitor (set for 1.275v in BIOS) for about 3 months running 24/7.

This is the second processor that I've had die on me in my life (first was an Athlon XP). I don't know whether to think it was a fluke that it died, or possibly the "high" Vtt.

It was running at 4ghz under water, so it never really ran too hot. I also checked the contact pads on the bottom, none showed any sign of scorching or discoloration.

 

[EarthwormJim]

Ya exactly

I am pretty sure I'd rather run Vtt of 1.25V (which is only 3.3% higher than maximum recommended) and VCore of 1.312V vs. 1.408V which is 7.3% higher, and bound to shoot up your temps into the 80s. I am constantly amazed that you can push an Intel processor really far, but my friends are now on their 3rd-4th Xbox360. Quality control !

Keep in mind that 1.25v Vtt is out of spec, 1.408v core is not out of spec.

 

[Rubycon]

How many of you are actually verifying voltages with a GOOD DMM? Some enthusiast boards include testing pads for this purpose.

I tested mine and was surprised! Both VCORE and VTT were considerably UNDER what was shown in e-leet, the EVGA utility.

 

[MadScientist]

my settings:

What load temps are you getting at that vcore? The Cooler Master Hyper 212 Plus is a good but not great heat sink. And what program(s) are you using to test stability?

Aren't you a wee bit worried about running at this vcore on this MB? TH fried 2 of these at 1.40V. http://www.tomshardware.com/reviews/...d,2436-15.html

My current settings are 3.70Ghz@1.325V bios, VTT 1.219V, PCH 1.100V, PLL 1.903V, Dram 1.601V. This is LinX, 50 runs, all mem, stable.

Anything over 3.7Ghz is not LinX stable (fails after just 1 run) up to 1.35Vcore, and on this MB I'm a little wary of going any higher.

 

[EarthwormJim]

How many of you are actually verifying voltages with a GOOD DMM? Some enthusiast boards include testing pads for this purpose.

I tested mine and was surprised! Both VCORE and VTT were considerably UNDER what was shown in e-leet, the EVGA utility.

I suppose I'll do that when my replacement CPU comes.

 

[BababooeyHTJ]

Keep in mind that 1.25v Vtt is out of spec, 1.408v core is not out of spec.

Exactly, which I still find to be very odd. There is just so little overhead on the recommended VTT on these chips.

What board were you using when the chip died on you?

@ Madscientist Why do you need so much PLL and VTT for that matter? What base clock are you running?

 

[spinejam]

What load temps are you getting at that vcore? The Cooler Master Hyper 212 Plus is a good but not great heat sink. And what program(s) are you using to test stability?

Aren't you a wee bit worried about running at this vcore on this MB? TH fried 2 of these at 1.40V. http://www.tomshardware.com/reviews/...d,2436-15.html

My current settings are 3.70Ghz@1.325V bios, VTT 1.219V, PCH 1.100V, PLL 1.903V, Dram 1.601V. This is LinX, 50 runs, all mem, stable.

Anything over 3.7Ghz is not LinX stable (fails after just 1 run) up to 1.35Vcore, and on this MB I'm a little wary of going any higher.

I lowered my o/c to 4.0 again b/c of heat -- into the 80's w/ stress-testing!

The newer bios' (2.00+) have "overcurrent protection" which wasn't present when these boards were toasting.

a quick ss of prime95 to get an idea of my temps @ 1.38 vCore:

 

[EarthwormJim]

Exactly, which I still find to be very odd. There is just so little overhead on the recommended VTT on these chips.

What board were you using when the chip died on you?

Why do you need so much PLL and VTT for that matter? What base clock are you running?

Asus P7P55D-E. I was running around 1.3v Vtt ( I can't remember, might have been 1.25 or so), 1.275 vcore and 1.5 vdram. The chip was running at 4ghz (183 bclk x22).

 

[balooo]

Interesting reading here.
I noticed in the intel technical documentation for the Xeon X 3 series (socket 1156) the Vtt can reach a max of 1,4V (Data Sheet Volume 1,page 69 table 7-4).Can there be such a big difference between the Core i5/i7 1156 and the Xeons , as i don't think the cpu's are so diffeent.Me and some friends are running X3440 and X3450 since oct/nov 2009 and only one had the burned socket failure at pretty high Vcore and Vtt voltage and i'm rather inclined to think it's the low pin contact pressure than the voltage.It was a Asrock P55 pro board.

 

[EarthwormJim]

Interesting reading here.
I noticed in the intel technical documentation for the Xeon X 3 series (socket 1156) the Vtt can reach a max of 1,4V (Data Sheet Volume 1,page 69 table 7-4).Can there be such a big difference between the Core i5/i7 1156 and the Xeons , as i don't think the cpu's are so diffeent.Me and some friends are running X3440 and X3450 since oct/nov 2009 and only one had the burned socket failure at pretty high Vcore and Vtt voltage and i'm rather inclined to think it's the low pin contact pressure than the voltage.It was a Asrock P55 pro board.

Very good bit of info. I can't imagine the Xeon LGA 1156 parts and Core i5/i7 parts are that different.

Maybe the higher voltage isn't "allowed" on retail chips due to heat concerns for consumers?

 

[RussianSensation]

It could also be that Intel wanted overclockers to buy into their higher end 1366 CPUs and X58 chipset to reap greater profit margins hehe. "Hey guys, quick, let's change the Vtt to 1.21V from 1.40V on 1156 so those budget overclockers don't get any ideas ah!!!"

 

[miahallen]

Maybe the higher voltage isn't "allowed" on retail chips due to heat concerns for consumers?

Actually, heat is a much greater concern in the server space.

 

[MadScientist]

Exactly, which I still find to be very odd. There is just so little overhead on the recommended VTT on these chips.

What board were you using when the chip died on you?

@ Madscientist Why do you need so much PLL and VTT for that matter? What base clock are you running?

Sorry about the delay, didn't see your question until now.

I'm running at 185 Bclk, 20 multiplier. In turbo mode I can run at a 21 multiplier but that didn't help stability. I still needed 1.325 vcore (bios) at 3.7Ghz to be LinX stable. I tried lowering PLL and VTT voltages in many combinations, but errored after just a few runs. I think my i5-750 is just a crappy overclocker.

 

[juliancahillane]

Hi fells Ive been having the same issues, glad I found this thread, ive been trying to get to the bottom of a related problem, my thread is over on overclock.net

http://www.overclock.net/intel-cpus/755422-i5-overclocking-4ghz-problems-5.html

 

[Supersonic64]

Well I'm glad I went i7-920 instead of i7-860, a few bucks more yes, but I get higher voltage tolerances and apparently easier to overclock.

 

[mrsparkle1811]

Sorry if this has already been posted but Intel have adjusted the specifications this month. Refer to the datasheet in the first post.

Vcc Absolute Max is now 1.4
Vtt Absolute Max is now 1.4
Vddq Absolute Max is 1.8

Nice to know we can now push higher overclocks while still remaining within absolute maximum spec.

 

[EarthwormJim]

Sorry if this has already been posted but Intel have adjusted the specifications this month. Refer to the datasheet in the first post.

Vcc Absolute Max is now 1.4
Vtt Absolute Max is now 1.4
Vddq Absolute Max is 1.8

Nice to know we can now push higher overclocks while still remaining within absolute maximum spec.

Awesome first post!

Good to know that the specs have changed.