Mini Tutorial for i5 750 Overclocking

[Dr.Paneas]

Get into the BIOS and load optimized defaults. Disable any spread spectrum settings, EIST, Turbo Mode, C1 and lock your PCI frequency to 100MHz and enable LLC. Ok now, you can finally Save and Exit from BIOS

Then log back in to Windows and stress your system for 5 minutes using Prime95's blend. WARNING: Do NOT use IBT or Lynx. At least I personally try to keep avoiding them cause they are too excessive stressing tools for my appetite. While you'll been stressing with Prime95, please open CPU-Z and observe the Vcore behaviour. This, my friend, is your actual stock Vcore ( aka VID ).

So go back into BIOS and set your Vcore to VID's value. Then stress your system for a couple of hours just to make sure that you are stable at stock settings.

Ok, since you know that your system is stock stable, then you can proceed with overclocking your computer.

Let's start finding at first your base clock freq. As far as you may be concerned bclock affects 4 crucial parameters:

1. Memory

2. Uncore

3. CPU

4. QPI

Let's have a little talk about them and try to isolate the bclock. We try to isolate this, cause we need to know our max bclk without any other concerns.

1] Memory isolation

Memory defines your RAM's frequency.

Math: bclock * memory_multiplier = RAM DDR speed

for example: 133 * 10 = 1333MHz

So I want you, to drop your memory multiplier down to the lowest value.

This means that you can overclock base clock without being concerned of overclocking RAM simultaneously. Please DO NOT overclock pass your RAM's stock speed.

I mean, you wanna catch 4GHz, right ?

You want this: 200 * 20x = 4GHz , am I right ?

So, if you drop your memory multiplier down to 8x, your memory would be running at 1600MHz ( 200 * 8x ). So, I need you to be aware of your RAM stock speed, in order NOT to overpass it !!!

2] Uncore isolation

Uncore, which means everything else but core. Such as L3 cache and IMC of the CPU. Your Uncore freq should be >= of your 2*memory clock. Which means you must have at least the double multiplier of your memory.

eg. Memory: 8x133

Uncore = 16 (or more) x 133

3] CPU isolation

Ok, you want 200x20, but let's find out the max bclock first. We do not want to overclock the processor. The i5 750 stock speed is 133x20=2.67GHz, so please DO NOT go beyond this frequency. I want you to overclock the bclk, not the CPU. So, drop down the CPU multiplier to 12x .

Do you wonder why ?

Well, is obvious: 200*12x = 2.4Ghz which is < 2.6GHz stock freq .

4] QPI isolationI do not know if there is a BIOS option for this to be refined. All I know is that QPI freq should not to change. So, if you are able to underclock its multiplier, you better do.

Last thing: set your Southbridge voltage to 1.3 Mhz.

Ok, Save and Exit. Go and test your new underclocked system. Stable enough ?

Let's burn it ( just kidding )

Start itching up your bclk with step of 15. Every time you overclock it you need to stress it, in order to test if the new bclock setting is stable. So use Prime small FFTs instead of blend test.

As a rule of thumb you will catch up to 150MHz without increasing any voltages ( I hope you are lucky ).

If your system become unstable try to raise VTT. Nothing else.

Just VTT. Got it ? Intel claims that the max safe VTT is 1.35, but a lot of people use 1.4 as their safe-wall.

[jordanis]

πολύ καλός οδηγός . μπράβο

[Dr.Paneas]

Thank you Jordan