Overclocking i5 750

[nibbler]

I'm getting one of these as soon as january starts. I have an H50 with a scythe gentle typhoon on it. What kind of overclock should I aim for? I kinda need the extra fps as I am a bit screwed in terms of the graphics budget :x. Would 4 Ghz at about 1.4v be a good target? I have RAM that goes up to about 2200mhz so that shouldn't be a limiting factor. Rest of system is an antec 300 with all possible fans on bar the side panel 120mm fan mount. MSI GD65 and an enermax PSU. Should i set the H50 as an intake or will it be fine as outtake (custompc seem to think that putting it as an exhaist near another large exhaust (namely a large 140mm fan right next to it like in the antec 300) will limit the cooling as the air 'prefers' to flow through an unimpeded fan than a radiator. Personally I think personifying the air shouldn't enter into it but is this important?

Cheers.

[sadbuttrue]

From the testing I've done, which contradicts almost every overclock you'll find on the web, the i5 750 needs high voltage on the vtt to be 100% stable. You can run it at 4ghz @ 1.35v vcore/1.2v vtt and have it pass all the usual stress testers (lynx 2 hours, prime95 blend 8 hours, prime95 small fft 8 hours, memtest86 10 hours), but it isn't "100% stable". The problems arise when you start loading the memory beyond 3gb during normal operation.

For example, with 2.8gb of memory in use (development machine) one may decide to have a quick game, pushing memory load close to 4gb. This produces the same result with a low vtt every time. Programs (starting with the game itself) will crash and windows will lock up. I've repeated these tests dozens of times. At 4ghz anything below 1.3v vtt crashes in this condition, with it happening once at 1.32v. For "100% stability" I settled on 1.36 vtt and 1.35v vcore, other components listed on left.

[nibbler]

1.35 vcore is decent then? I hope the H50 would be up to the job as an exhaust? VTT is the IMC really isn't it. Makes sense that it's linked to RAM usage. Also, what are PLL, PCH and that lot?
Thanks a lot,

[sadbuttrue]

The max for this chip as per intel specs is 1.4v vcore, 1.21v vtt. Everyone seems to be pushing the vtt upto 1.35v and claim this to be safe for 24/7 use. PLL and PCH are at stock, but the common figures others use for 4ghz is 1.9v PLL and 1.1v PCH.

Overclock guide for your motherboard: http://www.bit-tech.net/hardware/cpu...-core-i5-750/7

I had a H50 on this chip at 4ghz. I'm in the process of upgrading to a full watercool system, so sold it and am using an air cooler at lower clocks for now. You need to have the fan pushing air through the radiator, but it doesn't really matter if its pushing in or out. Pushing in will raise system temp, so personally I wouldn't go that route. I never tried a single fan configuration. With a push pull setup core temp registered 33c idle, 48c prime95, 60c full lynx load @ 18c ambient.

[nibbler]

Single fan as in on the corsair h50? I could do push pull I guess but it makes like 1 degree difference looks ugly and takes up too much room :/

[sadbuttrue]

The corsair fan pushes a decent amount of air, so as long as you mount it to push air through the radiator it will do good job. My setup was with the corsair fan pushing air through and an NMB running at 7v pulling air out.

[nibbler]

I'm just going to use a single 120mm scythe gentle typhoon but out of the case, not away from the radiator. Exhaust as opposed to intake

[nibbler]

Did some more testing today and I noticed something odd. In BIOS the vcore is currently set north of 1.4v (1.42 or something) yet CPU-Z detects 1.35v at the moment. This figure was higher earlier. Is there something odd going on? Huge vdroop?



Screenshot

[Terbinator]

Have you changed the vDroop setting to low vDroop in the bios? Anandtech seem to have found the same problems (well same experiences) that i have with MSI's P55 boards - It's that there is an issue with voltage not being set/reported properly by the bios (they're review of the P55 Trinergy board says MSI will be pushing out anew BIOS) theres also the issue of RAM tmings which have been driving me mad.

[nibbler]

on the other hand I'm happy that it's stable at 1.35v . If it vdroops but it stable below 1.4v then it's all good . Weird thing is it wasn't prime stable even at 1.4v :S

[Terbinator]

on the other hand I'm happy that it's stable at 1.35v . If it vdroops but it stable below 1.4v then it's all good . Weird thing is it wasn't prime stable even at 1.4v :S

I ran an hour and half of linpack test with a modest overclock (around 21x170BCLK) fine with no errors then the next day it just forza after about 10mins usage, still trying to get into this i5/7 overclocking lark :|

[nibbler]

my guess is that it wasnt stable at 1.4v vcore because it drooped to about 1.3 which is too low. This is annoying . I can't see the vdroop setting. I am running like the release bios though, this board was bought on launchday and has the bios it was shipped with. How do I change my bios?

[Terbinator]

my guess is that it wasnt stable at 1.4v vcore because it drooped to about 1.3 which is too low. This is annoying . I can't see the vdroop setting. I am running like the release bios though, this board was bought on launchday and has the bios it was shipped with. How do I change my bios?

You will have to go to MSI's website search for you board and it has all the BIOS versions released (your running 1.2 then like mine originally was i suspect)1.5 is currently the latest release. you can either update through windows or the bios itself by copying the new bios firmware to a memory stick and loading it up with the BIOS built-in updater.

Warning: BIOS flashing is potentially risky and could cause your board to 'brick'and its usually only advised if your rexperiencing problems with the current revision - but seen as you've been overclocking i don't think your too bothered

[nibbler]

I downloaded 1.5 patch but I don't know what to do with it . How do I do it through windows?

[Terbinator]

I couldn't get it to work through Windows using MSI's utility so i did it via USB, sorry

[nibbler]

And to do via usb? Just put on usb stick and then there's an option in bios?