Gigabyte P55 UD3R with i5 750 Question

I'm working on OCing this system with the Gigabyte P55 UD3R and i5 750.

This is a very new platform for me as my previous system was 4 years old, so OCing this has been a bit of a learning experience.

I've been using the following article as somewhat of a guide:

http://www.xbitlabs.com/articles/mainboards/display/asus-p7p55d-deluxe_7.html

So far I've determined my Uncore freq is good to 200Mhz at 1.19V

I've determined the Megahalem cpu cooler keeps the CPUs below 65C at 1.312V and 3500Mhz running LinX.

So now I'm trying to find the best overclock settings to allow for dynamic CPU speed and Vcore to be utilized.

Now for the problem...

Once I enable base clock control (BCLK) in the BIOS, for whatever reason all the dynamic characteristics no longer occur. Instead of the multiplier changing from 9x to 24x depending on load, it stays at 21x. The voltage also does not drop at idle, but remains at its current setting of 1.25V.

The current BIOS is the latest at version F4.

Everything is set to its default setting except:

blck control = enabled
blck freq = 175
QPI/Vtt Voltage = 1.15V
CPU Vcore = 1.25V
SPD = 6.0 (mem timings set to 8-8-8-22 using OCZ Platinum 2x2GB DIMMS)
Load Line Calibration = Enabled

Is it a feature or bug of changing blck control to enabled disables the dynamic frequency and voltage?

The highest I could run mine was 160MHz bclock before power features automatically shut off

http://www.overclockers.com/review-and-overclocking-results-of-the-gigabyte-ga-p55-ud3r-motherboard/

MIAHALLEN said:

The highest I could run mine was 160MHz bclock before power features automatically shut off

http://www.overclockers.com/review-and-overclocking-results-of-the-gigabyte-ga-p55-ud3r-motherboard/

Click to expand...

I had read your review, but I didn't see mention of the power features going away when the bclk was raised...so thanks for the heads up on that. The board must shut those off when it realizes you're OCing. I'm not sure why though. I also lost my 24x multiplier for single threaded apps.

I did enable EIST and regained some of the power saving as it reduces the multiplier to 9.0X under light load and idle, but the voltage does not drop.

I tried enabling the C3/C6/C7 state on bios version F2 and got a blue screen during windows boot. I've not tried enabling that with the new F4 BIOS but will try that tonight.

So far I'm at 180 BCLK with 1.248 Vcore and 1.15 Vtt (3780Mhz CPU). The OCZ Platinum memory is set to SPD 6 (1080Mhz) at 8-8-8-22 and 1.5Vdimm. I ran Prime95 torture in blend mode 4 threads for 8 hours without a hitch and the max temps CoreTemp saw was 58C.

I think this has quite a bit left in it, I'm just not sure how far I really wanna push it for every day use.

Actually, as I think a bit more about it...power C-states only worked for me when my vCore was set to [auto], and my highest overclock there (with some basic stress testing) was 160MHz bclock. I think I was able to reach that with zero modifications in the BIOS...everything on auto.

Power usage scales in a linear fasion with clock speed...but exponentially with voltage. In otherwords, eist will only save a little power, eist + C-states will save a lot!

I recently became more concerned with my power usage as well, my i7 920 is now clocked with all CPU features at stock, and blclock at 160MHz, which gives me 3360MHz CPU frequency while loaded and 1920MHz at idle...but it's saving me about 80W at the wall at idle and 150W at load compared to my "normal" 4.2GHz clocks.

MIAHALLEN said:

Actually, as I think a bit more about it...power C-states only worked for me when my vCore was set to [auto], and my highest overclock there (with some basic stress testing) was 160MHz bclock. I think I was able to reach that with zero modifications in the BIOS...everything on auto.

Power usage scales in a linear fasion with clock speed...but exponentially with voltage. In otherwords, eist will only save a little power, eist + C-states will save a lot!

I recently became more concerned with my power usage as well, my i7 920 is now clocked with all CPU features at stock, and blclock at 160MHz, which gives me 3360MHz CPU frequency while loaded and 1920MHz at idle...but it's saving me about 80W at the wall at idle and 150W at load compared to my "normal" 4.2GHz clocks.

Click to expand...

I'm going to play with the C states some tonight to see what I can find. Another member here says he has this same Gigabyte board and that I need to set the VCore as an "offset" to the nominal Vcore in order for dynamic power state to work. I've looked through the BIOS settings and I don't see a "VCore Offset" setting on this F4 version of the BIOS.

I'm downloading the latest copy of the manual now to see what it has to say.

Cool, good luck. I really didn't spend much time looking into that type of stuff...sorry I can't be more helpful. Let me know how it goes

The manual makes no mention of a Vcore offset either. More investigation is needed. I've sent a PM to the member who informed me of this setting to find out where it is.