i5 750 Overclocking help

Unbreakable

Unbreakable

Unbreakable

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Well iv finally got some spare time to have a go at overclocking my new rig. Only problem is I dont really know where to start. Been doing a lot of reading up on this forum and the net but am still unclear what settings to aim for to keep everything within safe limits.

Any advice would be most welcome.
 
Leave the voltage on auto for now. Download CPU-Z from Guru3d (I think...).

That will tell you what the stock voltage is (VID).

Then set the CPU voltage to this figure in the BIOS, and begin by raising the base clock. It's best to control the voltage yourself when overclocking, as auto can just go a little high sometimes.
 
Unbreakable said:
Is it safe to leave the voltages on auto?
Click to expand...

No not really or at the very least not advisable.

Re your OP it depends how far you're going to push it really. If you wanted a moderate overclock to say 3.2GHz ish then you could probably do it without having to raise any voltages or possibly only a tad extra vcore.

Here's what I would do:

Reset to defaults in BIOS if you've changed anything.
Turn off any powersaving features etc. (EIST, C-States, C1E, Turbo).
Set PCI-E frequency to 100.
Manually set volatges to default values (Vcore, VTT, PCH, PLL, DIMM).
Change BCLK to 160 and multi to 20 (3.2GHz).
Check RAM divider is set to run your RAM within limits.
Boot and stress test using prime, IBT or whichever you like.

If it's unstable increase Vcore a notch or two and try again. If it's stable you can either leave it as it is or try decreasing the Vcore if you want to stick at 3.2GHz. If you fancy pushing for more increase BLCK a bit at a time and retest increasing Vcore a bit when failing. You will need to raise VTT a tad when you start getting high up.

I'm currently running my i5 at 3.99GHz (190x21) with EIST, C1E and Turbo on. Only voltages I have had to change are Vcore 1.325v and VTT 1.175v. Since I have speedstep and c1e on the Vcore drops to around 1.07v when idle or under low load.
 
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Vcore - ~1.15-1.25 (max 1.4V, abs.max. 1.55V)
VTT - 1.1V (1.15V max, abs. 1.21V)
PCH - 1.05V (1.1V max)
PLL - 1.8V (1.9V max)
DRAM - 1.5V (1.65V max)

Make sure you've got your RAM set to the rated timings as well as DRAM voltage.

Drop the RAM multiplier by 1 before you start ocing (manually set it to 4x/8x)

VID does not matter, just set your Vcore to 1.2V manually.
 
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Thanks for all the great info.

The ram i have is corsair dominator CMP4GX3M2A1600C8

The rated times are 8-8-8-24. I should manually change the ram to these values?
 
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Currently using these settings

Vcore - 1.15
VTT - 1.1V
PCH - 1.05V
PLL - 1.8V

DRAM - 1.5V
RAM Multi - x8
Timings - 8 8 8 24

QPI Clock - x32
BCLK - 160
Multi - 20

Running prime just now and getting temps of 58-62C
 
Looks like it's 1.65v for those sticks. Temps look ok, what cooler are you using?

What voltage is CPU-Z reporting for Vcore? Is LLC on?
 
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Hello,

I have the same CPU and mobo, 4GB Corsair XMS3 (rated 9 9 9 24 @ 1600MHz @ 1.65V) and a H50 to keep it all frosty. You flashed the latest UD5 bios - f9?

I'm running 4.0GHz with 20x200 settings. QPI multi x32.
Ram XMP disabled, but ram set manually to x8 multi and performance enhance 'Turbo' (which auto sets 9 9 9 24 timings for me).
Dont have the sweetest i5 ever made it would seem, so need some fair volts for stability at 4GHz. H50 keeps it all under control though.

Vcore - 1.375
VTT - 1.3V
PCH - 1.10V
PLL - 1.9V
RAM - 1.66

I find it best with LLC on level 2. Standard or level 1 gives huge Vdroop under load (maybe due to rubish PSU not sure) which means I have to have a higher Vcore BIOS/idle setting so that it remains high enough under load. Level 2 LLC causes Vcore to raise slightly under load so it actually drops a little at idle which is the way it ought to be.

Have turbo, EIST and C1e all disabled, but now I know I'm stable I may look into re-nabling some of these features.

Good luck
 
Just keep trying lots of combinations + clocks,

I use Prime95 for stressing it, it will easily find a problem if there is an issue.
Then use something like CoreTemp to monitor the Temps, i have Found myself some nice Clocks + volts, i'm getting 3.6 on 1.25vcore, 1600mhz ram, with around 67*c temp full load, think i have found a sweet spot for my cpu :)

Just keep fiddling, not every cpu + motherboard ect are the same so everyone is pretty much different!
 
Quick question - does the DRAM voltage make any difference to the maximum baseclock, if the RAM is still running at or below it's rated speed? Because my sticks are supposed to be 1.6 / 1.65 V, but they are perfectly happy at 1.5 (memtest for 8 hours).
 
wilko49 said:
Quick question - does the DRAM voltage make any difference to the maximum baseclock, if the RAM is still running at or below it's rated speed? Because my sticks are supposed to be 1.6 / 1.65 V, but they are perfectly happy at 1.5 (memtest for 8 hours).
Click to expand...

No, the dram voltage applies only to the ram.

It's quite normal for good quality ram chips to run fine undervolted.
I always keep mine at the spec though just in case stability checks didnt catch anything (8 hours of testing is not enough to guarantee thousands of hours of stability).

The manufacturers test the chips for a lot longer than you would be able to and if all of their chips were able to run with lower voltage then they would spec them like that.
 
thanks rickh, was a little confused by Mr Krugga's post, cos that's what it seemed to be implying. And you are right of course, but this was the default voltage, and I didn't change it - no BSoD yet *crosses fingers*
 
wilko49 said:
thanks rickh, was a little confused by Mr Krugga's post, cos that's what it seemed to be implying. And you are right of course, but this was the default voltage, and I didn't change it - no BSoD yet *crosses fingers*
Click to expand...

The guy will be pushing bclk further to achieve a higher CPU clock. It increases both CPU and memory frequency. To stay within reasonable limits and make sure that the memory isn't holding you back, you have to up the voltage a little. That's all I was implying :)
 
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