krauley

ualdayan

You can read more about it here: Link

Basic gist is Intel says above 1.15V and below 1.21V you decrease the lifespan of your CPU but if you return it back to 1.15V you should be ok.  If you go above 1.21V VTT it can cause permanent damage that even when reverting to stock settings will persist.  (these are for Lynnfield -- Bloomfield (1366) can take higher voltage)

The same spec sheet says the absolute maximum VCore you should run is 1.55V.  That tells me it isn't just a case of Intel being too conservative.  Running VTT at 1.4V is almost like running your VCore at 1.7V if you look at what Intel says the absolute maximum the chip can take before damage occurs.

my p55ftw is at default stock settings in the bios with the exception of running raid 0 but my cpu vtt is at 1.34v, how can 1.21v vtt be max. everything is on auto in the voltages and frequency tab. the link you gave was to another forum but not to an actual intel spec so im going to go search for more info on this. thanks for the heads up though

That post has a link to the official Intel specification sheet, and also tells you the page to read (67).

If the P55FTW greatly overvolts the VTT by default that just shows that EVGA believes that VTT to be ok, but then they could be mistaken couldn't they?  Who do you trust more to tell you what can damage your processor - your motherboard manufacturer or the company that made the processor?  Remember - voltages on AUTO are set by the motherboard maker, the CPU doesn't tell the motherboard what voltage to run it at, the motherboard is suppose to recognize the CPU and set the proper voltages.

There were people who said their Bloomfield's ran at 1.6VTT just fine, but then others claimed it killed their CPU - every CPU is different in what it can take before failure, and you might never know damage is being done until 3 months later when suddenly a stage in the IMC fails and it doesn't turn on at all anymore.

Here's the direct link to the spec sheet: http://download.intel.com...or/datashts/322164.pdf
Turn to page 67 for standard, safe VTT (1.15), and absolute maximum VTT (1.21V) specifications.

krauley

ok read what it says about the dimm voltage on the same chart.....

you can tell me that this board wont run ram higher than 1.65 when some of the approved ocz run higher? i see that chart but im not sure if its  real conservative ratings or what.

Actually, yes, you aren't suppose to run DRAM above 1.65V or you do risk permanent damage. There should have been a sticker over your memory slots that had it in bold that you absolutely should not use the older 1.9V DIMMS that were meant for earlier processors.  Here's what the sticker said: "“According to Intel CPU SPEC, DIMMs with voltage setting over 1.65V may damage the CPU permanently. We recommend you install the DIMMs with the voltage setting below 1.65V.”"  DDR3 standard voltage is 1.5V, but the early ones meant for C2Q processors specified 1.9V or even higher to run at faster speeds.  They are NOT intended to be used with an i7/i5 processor, not even a Bloomfield (1366) one.

You might remember this from Anandtech back when the i7's first launched: http://www.anandtech.com/.mory/showdoc.aspx?i=3426
"Numerous articles and forum posts have been popping up recently about the potential of high VDimm settings damaging or destroying the upcoming i7 processor series. Will high VDimm cause damage? The answer to that question is not so simple actually.  Intel’s stance is clear on this subject, run VDimm higher than their 1.50V~1.65V guidelines and you will affect the life span of the processor.

We have already witnessed several CPUs being damaged or destroyed at the motherboard partners with high VDimm settings, especially those that ran at 2.0V or higher with base settings. By base settings, we mean configuring an i7/X58 platform in the same manner a typical user now sets up a Penryn/X48 DDR3 platform. The rules have changed completely for Intel"

i just flashed from A48 to A51 and one thing i noticed was that my vtt was at 1.12 before i set my memory to XMP, my timings, and my voltage. then it jumped back up to 1.34v where it was running.

here is my ram:  http://www.newegg.com/Product/Product.aspx?Item=N82E16820145268

thing is that most of corsairs ram recommended for i5 & i7 on newegg are at 1.65v. im going to hold off and working on my O/C of this board until next week after the last of the holidays that way the KIDS will be back in school. My quiet time! :P

Edgar2904

Put my P55 FTW i7 860 rig together like 3 weeks ago and it is still on the assembly table. Reason: after Win 7 and E-fleet was installed I started looking at my Memory & CPU voltages. That stuff got me worried! CPU temp was around 40C. Vtt was above 1.2V, Vdimm was above 1.65V. This was with the memory set to the XMP profile!
I knew I shouldn't be going above a Vdimm of 1.65V. This was concerning. So after that I left it where it is to figure out all the default specs before messing with the system again.

Thing is, Intel CPU booklet doesn't mention anything about voltages. Motherboard booklet doesn't mention anything about any voltages. So what are the safe voltages for this system (motherboard/CPU)? The safe baseline, before overcloking? They are not the EVGA default voltages for sure!

I think these are what the 860 defaults to:
CPU VCore 1.25V
DRAM Up to 1.65V is safe, if memory states it needs over that you can try running at 1.65V and slower speeds.
VTT: ~1.10V, up to 1.21V is safe
PCH 1.05V is normal

The Vcore is going to fluctuate a lot though depending on if you have Turboboost turned on, or C1E, or Speedstep.  AUTO is actually pretty safe on Vcore, doesn't seem to be any confusion over what's safe there.

Stability ok after Prime95, 3D mark and PC Mark tests. CPU temp average during load is 55°C, PEAKS @ 78°C MAXIMUM during ms only. Vcore @ maximum 1,43V. System pretty stable. But for everyday use, I'll go back to a middle OC, not useful to have a 4.2 for backoffice, audio and internet use.

Hey thank you ;) I'll upgrade. EVGA E Leet reports also major temps, the 2 temps panels of the P55FTW too but realtemps is very nice too.

Scaniris

Hi,

here is my OC using settings provided here, but with a 2000MHz memory setup:

I'd like to see your "Monitoring" tab from E-Leet.

Hi Dyphen ^^

I have the same issue with my P55 SLI + i5 750. Some BzzzBzzzBzzz when speedstep is active.

My powersupply is a Seasonic 430W so I don't think that your problem comes from your Corsair.

The load on the CPU power line will vary with speed step enabled depending on usage. When multiplier decrease, voltage also decrease at the same time, and power load too. With C states same story. Some PSU are buzzing (condensators) when no load or load change on a power lane. I had a Seasonic M12D 850W. The PSU was buzzing when the PC was down or soft off, and the PSU was buzzing when power requirements were dynamically decreased by the embedded technology (Speed Step, C State, but also Powerplay etc...).

Did you locate the buzzing into the PSU? Is it buzzing, or tweeting (high frequency)? Strange that this happens on 400w psus. In some Hifi components I also had some buzzing issues with a class and ab class transformers. Sometimes because of a condensator, sometime because of the thoroidal tranformer...

To make sur the buzzing is linked with speed step mode, let's start CPU Z, and wait until the multiplier decrease to x9 for example... then start an application, multiplier will increase up to x20, x21 depending on settings maybe more if turbo mode is on. If the buzzing appears only with low multiplier... it's probably coming from the PSU when load is decreasing on the cpu power lane.

I have older hardware components than most of you, guys (and you can check them by clicking on my signature). I also get that buzzing sound from my PSU though it's very rare and barely audible. It happens once or twice a week and lasts for about 10-15 seconds. Why? I don't know!

By the way, I've written to EVGA_JacobF about the voltage limits specified by Intel for the Core i7 7xx/8xx but he hasn't responded yet.

Would shamino have any insight? He's been posting recently.

Sgt.Steiger I'd like to see your "Monitoring" tab from E-Leet.

Here you can find some more details : http://www.xtremesystems....?p=4183957#post4183957 . @ 4.2, 3.5 with turbo, 4 or 2 cors etc...

And a screen shot with more details @ 4.2 directly here (you probably want to see voltage... CPUID HW monitor, but if it's really required I can do it again with monitoring from E Leet)

i have a 650w , and i just connected one 8 pins, i wait a new power supply ( HX1000w ) , i will connect both 8 pins with it

the sound that i hear , the buzzing comes from the top-left of the motherboard, so i guess it's the motherboard no ?
maybe because my power supply is not enough or because i dont have connected both 8 pins..

i will see with my new power supply

Thanks Scaniris.  That is excellent information.  Nice clocks!