Getting my i5 750 to 3.6...

[Carmen813]

I'd like to get my i5 750 stable at 3.6ghz. Right now I can boot into Windows all the way up to 4.0, but the heat at that speed is way higher than I'm comfortable with. I'd prefer to do a stock voltage overclock if possible, but I'm not sure how I can go about limiting the voltage to 1.25. Should I use offset mode or manual?

According to CPUID, my power draw is jumping to 1.32 volts underload, which seems a bit much.

You can see what my BIOS looks like here:
http://www.legionhardware.com/articles_pages/intel_core_i5_750_overclocking_guide,4.html

 

[biostud]

manual

 

[Bill Brasky]

manual

This

edit: BTW which version of the p7p55d do you have? Just curious.

 

[yh125d]

Can you not just leave everything default and set bclk to 180? Should be doable, maybe +.025v to the VTT

 

[Carmen813]

My memory is DDR1600, so I think a 200 Bclk is needed to have it run at stock speeds (I don't want to OC my memory just yet.)

I have a p7p55 lx. The cheapo board.

*Edit* Okay, so I set to manual mode and picked 1.25 volt. CPUID is reporting that it's running at 1.296 volts while idling. When under load, the voltage drops to 1.184v-1.25v (which seems like where it is supposed to be)....so...this seems backwards, what did I do wrong?

 

[yh125d]

160bclk with 10x multi would get your ram at stock speed, but ram speed doesn't really matter. I run my DDR3-2000 at only 1750

 

[Carmen813]

160bclk with 10x multi would get your ram at stock speed, but ram speed doesn't really matter. I run my DDR3-2000 at only 1750

I normally was running 160blck with a 20x multiplier, for a total of 3.2 Ghz. I'd like to push past 3.4. To do that, I set my Bclk to 200, my memory to 1600, and then my multiplier to 18. 3.6 is my target.

I'm running the intel CPU burn test right now with the manual voltage set to 1.25 volts. My main problem now is that my idle core voltage is around 1.296 volts, which doesn't seem right. I think perhaps I have an offset set incorrectly...not sure, I set it to manual mode.

 

[yh125d]

What do you mean offset? LLC?


Set eeeverything to default. Then...

bclk 180
cpu mult 20
qpi mult 18
ram mult 8 (or 2:8 depending on how your bios reports it
QPI/VTT stock voltage should be around 1.15, bump to ~1.17
vcore to 1.275

That should get you 3.6. I got 3.67 with 1.26vcore and 1.15 VTT without even trying to go lower, I'm sure you can at least get 3.6 with those settings. If you pushed vcore to 1.3 and VTT to 1.2 you'd likely get 4gHz

 

[Carmen813]

I meant the CPU voltage. I can choose manual or offset mode. If I set to manual, and put it at 1.25v, I was getting 1.3v in CPUID while idle.

*Edit* I don't have a lot of the settings you just mentioned. I can't adjust QPI multiplier (well, it gives me 3 options, auto and 2 frequences) or the ramp multiplier (it against just lists 3 frequencies. If I set Blck to 180 my choices are like 1440, 1800, and something lower than 1440).

*Edit 2* The problem I'm having is my idle voltage is higher than load voltage. I know I read an article somewhere on Anandtech that implies this was normal, but I can't find it. Anyone got a link to what I'm talking about?

 

[biostud]

I couldn't get my o/c stable with memory running 1:1 even though I have ddr3-2000 Mhz modules so I had to run a divider. (see sig)
memory speed is not that important anyway.

 

[Carmen813]

I couldn't get my o/c stable with memory running 1:1 even though I have ddr3-2000 Mhz modules so I had to run a divider. (see sig)
memory speed is not that important anyway.

I seem to be stable right now with where I am at. 200blck, memory set to 1600 Mhz (choices are something I ignored, 1600, and 2000). I think that means I have a memory multiplier of 8x, 10x, and possibly 6x (though it lists the frequency it will run at, not the multiplier, in my BIOS).

My main concern right now is getting the voltage setting right. It seems like no matter what I set it to in the bios, my CPU idles about .05 volts higher. For example, I've got it set to 1.23 in the bios right now, I'm idling at 1.28. I was able to complex 5 founds of the intelburntest at maximum settings with this.

 

[Carmen813]

Found the article I was looking for:
http://www.anandtech.com/show/2404/5

I'm now set to manual mode, and my CPU voltage is set to 1.20 in the bios. This results in an idle voltage of 1.25, which is where the CPU is specced.I can't get the CPU to boot into Windows if I try using the "offset" setting. I tried a few settings, with an offset up to .03, but it always results in a BSOD. It says in the manual I could set the offset voltage to a positive or negative value, but it seems to be fixed to a positive value in the BIOS.

Should I enable or disable Xtreme Full Phase Power?

 

[yh125d]

disable


your bios is wierd... I've never heard of offset in the vcore options (voffset option is different from vcore option)

 

[Bill Brasky]

disable


your bios is wierd... I've never heard of offset in the vcore options (voffset option is different from vcore option)

I could be wrong, but I thought the extreme full phase should be enabled so that the power saving features on the mobo are disabled. It even says in the bios that it should be enabled to provide a more stable OC. *shrug*

 

[yh125d]

I could be wrong, but I thought the extreme full phase should be enabled so that the power saving features on the mobo are disabled. It even says in the bios that it should be enabled to provide a more stable OC. *shrug*

Google shows nothing for "xtreme full phase power", and it sounds just like LLC, I'd leave it off. You can turn off the C sleep/halt states yourself.

 

[Carmen813]

LLC is a seperate setting. Xtreme Full Phase Power is an Asus motherboard function that turns off the EPU functions.

 

[Meghan54]

Google shows nothing for "xtreme full phase power", and it sounds just like LLC, I'd leave it off. You can turn off the C sleep/halt states yourself.

Google may not, but if you downloaded his manual, which took all of two minutes, you'd see that LLC is NOT the same as extreme full phase power.

To quote the manual:

Xtreme Phase Full Power Mode Enabled---Enables full power mode to ensure the best CPU overclocking performance.

So, the answer is to enable Xtreme Phase Full Power Mode.

Also, don't use offset mode. Put the VCore Over Voltage setting into Manual mode, not offset. This will allow you to set a fixed cpu voltage, not a drifting one that the offset allows. This setting appears when you put VCore Over Voltage in Manual.

In VCore manual mode, pick a voltage that's around stock and start there.

Turn off your Load Line Calibration.

Turn off Speedstep, at least when setting up and testing your OC stability.

Turn off Turbo Mode.

Put your memory voltage into manual mode and set it at what the manufacturer recommends for the speed it's rated for......

All the above is in the Ai Overclock Tuner BIOS page.



Then, go to the Advanced tab/page.

Enter the CPU Configuration section.


Turn off C1E.

Turn off Turbo Mode.

Turn off SpeedStep.

Turn off C-State.



You want to turn off all the energy saving features when you're first setting up an overclock. After stability testing, you can then start turning them back on if you wish, but check stability after you turn them back on.

Also, the reason you want to turn turbo mode off is you don't want a 3.6GHz overclock to suddenly become 3.9GHz or faster when the cpu is only using one core. Your voltage you're using, while stable at 3.6GHz or whatever OC you finally decide upon, may not be enough for that sudden kick in of turbo and can cause crashes, lockups, etc., not to mention higher temp.


And have fun. That cpu of yours should kick right up to 3.6GHz without too much difficulty at all.

 

[Carmen813]

Thanks a ton, very helpful!

 

[Meghan54]

Well, it's a start at least.

Just read the manual and ask questions if you need to.

And, yes, I've got one of my systems running an i5 750, albeit on a Gigabyte P55A-UD3, at 3.7GHz (20 x 185) at 1.120V, and it idles at 30C-32C with a rather small heatsink, the Arctic Cooling Freezer 7 Pro, Rev. 2.

And while it's a different motherboard, the concepts are the same.

I also am running an Asus board with my i7 920, so I do understand most of the Asus BIOS, too.

 

[Carmen813]

I set it to 1.21875 volts, do you think that is a good starting place? It seems idles at 1.24in windows. For whatever reason, the idle voltage is always a bit higher than what I set it to. Like there is a built in offset that I can't control.

And what do you suggest for hitting 3.6. Should I go with 200x16 or 180x16? Really the only difference that I can tell is that at 200x16 I can run my memory at its rated speed (DDR1600), where as with the 180bclk it runs at 1440 MHz. I don't know how important that is for performance, bit I think the lower Bclk can help with stability because it results in a lower QPI frequency. Does this all sound right?

What is C1E? Is it power saving, and would I ever want to enable it? I'm hoping to keep the power saving stuff on with a stable OC.

 

[Carmen813]

Okay I have a little more information. I've managed to get a stable 3.6 Ghz OC (completed 25 runs of the IntelMaxBurn test on max settings). I'm using 180x20.

I'm now working on the power saving features. I have Speedstep and C1E enabled. Bizarrely (to me), enabling C-States (and setting to C6) increases my idle voltage from 1.248 volts to 1.272 volts according to CPU-Z. I cannot for the life of me understand why it does this, but it does. Any idea?

 

[Carmen813]

Well, I think I finally figured out what was going on with the weird C-state voltages. Basically, with a fixed voltage, it only appears that C1 works properly. Setting to C3 or C6 results in a significantly higher voltage than what I set in the BIOS.

However, I decided to try playing around with overclocking using the Offset voltage mode, instead of manual. With an offset voltage of .075 volts, I was able to successfully boot into windows and complete 25 runs of the IntelMaxBurn test at 3.6 Ghz (180x20). This seems to be very stable. In addition, I was able to successfully complete the test with Speedstep, C1E, and C6 Cstates enabled. This results in the voltage acting properly, it ramps up when the chip is under load. Even better, my temperatures at idle and load are lower...maxing at around 62 c, Idling at around 18-19c. At load the CPU is drawing around 1.17v, maxing out at around 1.20v, which is still well below the Intel stated max of 1.25. My idle voltage is around 1.00v.

Hope this helps someone else with their overclock in the future. The offset mode overclock definitely seems to be the way to go if you want to keep the power saving features working properly, just be prepared for a lot of tinkering.