i5-750 at 4ghz

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psilence

Limp Gawd
Joined
Jun 1, 2009
Messages
167
Hello

I finally decided to stop being lazy and get my i5-750 up to 4.0ghz. I thought I would make this post in order to help anyone with a similar setup. Maxed at 70c with 50 passes of intel burn test, doesn't go over 50c with heavy daily usage.

http://i42.tinypic.com/t7zcex.jpg

Sig rig, settings as follows:

>>Advanced Frequency Settings
CPU Clock Ratio: 20x
QPI Clock Ratio: 32x
BCLK: 200
Extreme Memory Profile (X.M.P): Disabled
System Memory Multiplier (SPD): 8.0
PCI Express Frequency (MHz): 100
C.I.A. 2: Disabled
CPU Clock Drive: 700mV
PCI Express Clock Drive: 700mV
CPU Clock Skew: 0ps

>>Advanced Voltage Settings
Load Line Calibration: Disabled
CPU Vcore: 1.35000V
QPI/VTT Voltage: 1.150V
PCH Core: 1.050V
CPU PLL: 1.800V
DRAM Voltage: 1.560V
DRAM Termination: 0.750V
CH-A Data VREF: 0.750V
CH-B Data VREF: 0.750V
CH-A Address VREF: 0.750V
CH-B Address VREF: 0.750V
 
What cooler do you have?


And to anyone who thinks 20 runs of intelburn/LinX is enough is a fool.

you need at least 80 runs or more. i got errors after 40 runs.
 
Vonteme said:
What cooler do you have?


And to anyone who thinks 20 runs of intelburn/LinX is enough is a fool.

you need at least 80 runs or more. i got errors after 40 runs.
Click to expand...

Megahalem Rev. B (in sig..), and I ran 50 runs that time and 500 the night before. It's good to go, friend.
 
And to anyone who thinks 20 runs of intelburn/LinX is enough, you are fooling yourself.

You need at least 80 runs or more. I found errors after 40 runs.
Click to expand...

We do not call people names around here, even in backhanded ways or generalizations.

Fixed it for ya.
 
psilence said:
Megahalem Rev. B (in sig..), and I ran 50 runs that time and 500 the night before. It's good to go, friend.
Click to expand...


I have read lot of positive things regarding this cooler, however, where I live there's no option to buy it.

Really good temps indeed.
 
Here is my take on "load line"

To help protect the CPU from the normal and unavoidable spikes in CPU voltage caused by the CPU voltage regulation circuity "overshooting" the intended voltage when current loads rapidly change (like firing up a CPU intensive game or a stress program) Intel on purpose have the voltage regulation circuitry calibrated to provide slightly less voltage that what is called for and this difference changes as current and voltage demands increase. This is the load line. Pull the Intel data sheet for your CPU from Intel.com for more info.

So everything is a trade off, if you disable it you typically get closer to what you set in the bios voltages at the CPU (commonly called voltage droop) but if you run at the high end of recommended CPU voltages you incur some risk. For example a 45nm core Intel CPU usually has an Absolute max Vcore per the data sheet of 1.45 volts. The CPU voltage regulation circuit specs from Intel calls for a max overshoot of .05 V on big current load transitions with load line calibration off, you "safety margin" is reduced if you run a Vcore of 1.40 or more where you could exceed the max voltage rating starting up heavy duty apps from idle.

Now these CPUs are pretty hardy and people push them hard and have been for over 3 years now and it is amazing the abuse they will take. Also we don't tend to keep CPU's for 5+ years, not most of us. So the amount of risk is debatable.

I think:

If you turn it off and run the CPU under the absolute max Vcc from the data sheet by .05 volts or more I would think any risk would be very small.

If you leave it on and just compensate with a higher Vcc in the bios but not exceeding absolute max Vcc the risk would be very very small.

If you disable it and run Vcc at the absolute max Vcc you increase risk of CPU damage. If and when it would happen, who knows.

So unless you are way up there on Vcc in the bios it is not a big concern either way.

I think a lot of people turn it off just so they know the voltage they set in the bios is about what they get under windows all the time and eliminate the variations that the CPU voltage regulation circuit would otherwise try to make. This helps in OCing as you eliminate any chance a set of OC settings might fail due to those minor voltage changes you have no control of. So one turns it off so you know exactly what Vcore you are running at and it does not unexpectedly change.

Thats my best shot at it. My board does not have the option and the OP might have another good reason or first hand experience I do not.
 
Last edited:
Thanks for your explanation. I just wanted to make sure I got this... You're saying that higher vcore is needed in the bios with LL enabled than without right?
 
yes, to end up with a higher "actual" Vcore and closer to what you set in the bios you would turn it off. With it on you would usually need to set Vcore a little higher than what you really wanted and it would "wander" a bit depending on load.

I think I answered the question, it gets confusing, which is why I think most OCers just turn it off so you get pretty close to what you set in the bios.
 
Congrats on the 4.0Ghz!!:) Is Intel like AMD, like you have to get the voltage just right?
 
Spanky93 said:
Congrats on the 4.0Ghz!!:) Is Intel like AMD, like you have to get the voltage just right?
Click to expand...

Yes, it wouldn't work at anything below 1.35v, but at that number it magically ran everything.

I'm thinking I might have to dial it down though. I just bought a new home and this house is much warmer than my previous one (no shade vs surrounded by oak trees), so now my idle temps are about 8-10c hotter.
 
Or more, even. :(

2h3mno5.jpg
 
It's better on days when it's not horribly hot and humid out. On a normal night it seems to idle at 38c, not too bad.
 
BillParrish said:
We do not call people names around here, even in backhanded ways or generalizations.

Fixed it for ya.
Click to expand...

Good on ya, mate. Note my sig.

OP - glad that you shared, I'm hoping to push my 750 to at least 3.8 Ghz relatively soon. User experiences always help.
 
JaYp146 said:
Good on ya, mate. Note my sig.

OP - glad that you shared, I'm hoping to push my 750 to at least 3.8 Ghz relatively soon. User experiences always help.
Click to expand...

Glad to have helped. Load temps don't seem to have changed all that much for me (2-4c higher), so the move and new office aren't as much of a concern as I had thought originally.

162fxj.jpg
 
BillParrish said:
yes, to end up with a higher "actual" Vcore and closer to what you set in the bios you would turn it off. With it on you would usually need to set Vcore a little higher than what you really wanted and it would "wander" a bit depending on load.

I think I answered the question, it gets confusing, which is why I think most OCers just turn it off so you get pretty close to what you set in the bios.
Click to expand...

That is the main reason I've turned it off on my set up, just ease of use.
 
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