I5 BIOS temp observations


Sep 30, 2009
Hi, this is my first ground up build, originally intended to fit in a micro ATX, however due to a change of heart now transplanted to an Antec 300 with 4 fans, was hoping to do a small (4-600MHz) overclock but so far i'm a little unsure if i'm seeing something unusual:

An i5-750 on this board:


with this 2000MHz ram:


Stock intel cooler set to run at max
5870 pretty close by, the back gets warm.
Corsair 750W PSU

Haven't installed the OS yet, waiting for Win7 to arrive... So these are all BIOS reported values.

First boot successful, ambient temp 72 to 74F (22-24C)

Ram: 1333
FSB: 133
CPU multiplier: 20x.
All voltages and memory settings on AUTO
Vcore: reported around 1.286,
Vdram: 1.5
Core temps ~ 36-38C
12V rail: 11.985
5V rail: 5.052 (are these ok?)

Enabling the XMP memory profile + reboot
Ram: 2000
FSB: 200
CPU multiplier 13x.
Leaving everything else on AUTO except the PCIe which i set to 100.
Vcore was now being reported at around 1.35,
Vdram 1.664, which i manually adjusted to the next lowest - 1.648.
Core temps went up to the 40 to 45, no doubt because the Vcore was rather high.

Playing around to see how the motherboard responds, raised the multiplier to x14 (2.8) and x15 (3.0). Vcore remained the same (1.35) at AUTO, but temps rose to ~ 47. Manually dropped Vcore to 1.25 then 1.175, temps dropped to ~ 39 - 41. Still seems high to me... dropped it to 1.115, wouldn't POST - continual reboot. Cleared and set back to optimized defaults POSTed fine.

Does these stock idle temps seem normal? Is BIOS reported temp accurate? I was debating whether to get a hsf when I ordered everything a week or two ago, but ended up not doing so. Tried re-seating the intel cooler once (new thermal grease) because i've read other people are getting idle temps at 28. Made no change to the mid to high 30s @ idle. Now i don't really feel like pulling the board out to install a different cooler, so i'm getting a little concerned. When the OS arrives, i'm planning to run a few stability tests as described in the overclocking guides here, but at this stage i'm just looking for a little advice:

1) To ensure the OS install goes smoothly should i leave the BIOS configured at 133 FSB and 20x. No XMP?
2) Do these temps suggest that to run the ram at its rated speed of 2000 i should really get a better cpu cooler.
3) If it won't run at 2000, am i right in thinking the ram will be stable at other bus speeds below 2000, eg FSB 160, Ram 1600?
4) Is the stock Vcore similar to other peoples experience? Wandering if i can lower it a little?

Thanks in advance


Intel Master

Intel's stock cooler is very poor, and is barely adequate at stock clock. Definately replace it with a high-end cooler and a retention bracket, which you'll most certainly need if you're going to overclock. Also, the temperature you see in BIOS is CPU temperature, not Core temperature.

You won't be able to see Core temperatures until you install the OS and a monitoring utility. Real Temp displays Core temperatures and can be calibrated, while SpeedFan displays CPU temperature and Core temperatures, and can also be calibrated. Hardware Monitor displays both sets of temperatures, but can't be calibrated.

Lastly, auto Vcore applies significantly more voltage than is necessary, so it's always prudent to use manual settings, however, leave all settings at stock until your OS is installed. You won't be able to perform any meaningful stability and thermal testing until you install the OS and run Prime95 Small FFT's. For the present, you can work ahead by reading the i7 Overclocking Guide and Temperature Guide Stickies at the top of this Forum.

Comp :sol:


Sep 30, 2009
Thanks Comp,

I've been reading those guides a bit over the last few days, i guess what i'll do is look to optimize a fairly stock system, which i'll run for a while and see how the turbo mode behaves. I will replace the cooler once everything is up and running... I read that the board isn't really up to big overclocks, so i'll just see how things perform. Win7 arrived today, so i'll hopefully get more information tonight.

Thanks for your reply


Sep 30, 2009

Took me all night to install Windows 7, for some reason it kept hanging at the "windows loading files" screen. I finally got through it by re loading fail safe or optimized defaults in the BIOS. The only thing i'd touched was the boot order and disbaled the post image... hmm.

So got everything installed, only problems were the ATI HOTFIX drivers for a 5870 from their website caused all sorts of problems, so reverted to the ones on the cd and the drivers for the wireless PCI card dont work, (well windows says its functioning properly, however atempting to scan for networks throws an unknown error)

Then started investigating with CPU-Z, Speedfam, Realtemp and Prime95. Whatever the BIOS settings are at stock optimized the system was not very stable, it wouldn;t throw errors instead randomly hanging while doing nothing or go about 20min into a blend before everything froze, additionally while i was transfering files and messing around with unzipping various things, the screen would go blank, requiring a reboot. I'm wondering if this is a GPU driver issue rather than CPU.

Didn't have time to play with many settings but did enable the CIA 2 performance boost to the cruise, sports which made it into windows however the idle clock was near 3.4GHz, dropping to 2.66 under load (4 cores) and staying around 2.8 on 1 core? Everything except PCIe is on AUTO, CPU-Z reporting Vcc 1.214. Right now i'm just trying to get a stock system thats stable. So i disabled all the turbo features and all the safe guards. Tried a nominal Vcc 1.214, set the memory to factory timings and Vdram 1.65. Bumped Vtt up a notch to 1.15. Still had a couple of random blank screens after maybe 30mins of very light work, i must have disabled the power saving because it still sits at 1 - 2% load 3.4GHz ~ 30C, 100% load at 2.66 GHz ~ 65C (for any number of cores). I'm at work now so can't post any screen shots just yet.

Ideally i want to have the low power consumption at idle and high single core clock when loaded. Not really sure what i have to enable/disabled to get there. If anybody has an ideas please let me know.



Sep 30, 2009
Since my last post everything is now fixed, no blank screens or hanging. I wasn't really understanding what I was doing before...and had half the bios auto fucntions set to prevent what i wanted to do. Got it now, went through comps temperature calbration guide and read the i7 guide here as weel as an i5 overclocking guide on bit-net. Managed to get the clock to 3.6 (200x18) on the stock cooler that ran Prime95 small FFTs for an hour before i stopped it with no errors, Vcore need to be almost 1.35, may be able to do better with Vtt adjustment, i didn't try. Core temps got rather high though, into the 78-82 range, with the CPU fan on max. Reason i wanted a 200 clock was to see if i could get the ram to work at its XMP profile. This was with intel's turbo mode enabled so on a single core with Prime95 again the clock goes up to over 4.2 (21x200), occasionally touched 4.4 with temps in mid 50s. Very impressive.

For normal use and given the recent concerns about the 1156 socket i returned everything to stock then upped the bus a little to 140, Vcore at 1.212. Vdram at 1.65. Gives me a nice 2.8 on all 4 (65C load) and 3.36 or 3.5 (cpu multiplier can go up to 25x on this board) on single cores (<45C), idles at 1.26 0.8V (28-32C). Memory seems stable at ~1400Mhz. Speedfan reported Vdram 1.54. Not played with that or Vtt much, i'd like to be able to get 3.6 with a lower Vcore so perhaps i should. Looks like i should be able to run the XMP profile with an aftermarket cooler, just worried that Vcore required will be a problem. I read that anadtech fried an i5 at 1.3 something...maybe that was Vtt i can't find the ref now. Mine needed at least 1.275 Vcore to POST with 200 bus, booted into windows no problem but failed within 5mins on 1-3 cores Prime95 until raised to 1.35.

The guides here are very useful, a big thank you to Comp and others who wrote them. :)