Time to Tinker (2500k)

Phenomenologica · 12 Jun 2011 at 17:14

Yep, it's time for the 18,769th i5 2500k overclock thread!

Background here, I bought an overclocked bundle from OcUK and thus far it has served me well. However I'm bored and fancy fiddling with things a bit, so I had a look in the bios at the voltages etc. Turns out I'm currently on 1.344 Vcore, which I thought was a bit high for 4.4Ghz, so I'm wondering if there is room to up the clock or lower the voltages a bit there. Also, I noticed my RAM voltages are 1.548. I thought for Sandybridge it was advisable to keep them under 1.5, or was it just near to 1.5? It's 4GB of XMS3 running at 1600Mhz, if that helps.

I'm on a Gigabyte P67 chipset motherboard, and before I do anything I intend to familiarise myself a little more with the various screens and settings in the BIOS. But effectively I'm just upping the multiplier slightly and testing for stability while keeping an eye on the temperatures, correct?

orby · 12 Jun 2011 at 17:17

i am currently trying 4.6 gig at 1.32 volts in bios so you have room, just need to experiment, try rasing the clock or lower the voltage first and checking stability

Phenomenologica · 12 Jun 2011 at 17:31

Thanks for the comment orby, hopefully my chip won't be too awful.

I've had another look around the BIOS and am now confused. In the main panel of the 'Intelligent Tweaker' thing that constitutes overclocking in the Gigabyte BIOS, it gives the settings I mentioned before. But when I go into the screens where you can actually adjust settings, it shows the following:

CPU VCore - 1.340V [1.355V]
DRAM Voltage - 1.500V [1.500V]

Which doesn't correlate with the 1.344 and 1.548 shown on the main page, and the CPU one shows two different values on one line. Thoroughly befuddled. :confused:

Also, other settings I've seen mention of around here are XMP, PLL Overvolt, and Load Line Calibration. What should these be set to, optimally? Also, I found two settings, one of which stated a power limit set to 95 Watts, the other a current limit of 97 Amps. Should I leave them be?

And finally, the whole Turboboost malarkey. Currently it's set to auto, and one screen in the bios indicates that normally the CPU runs at 3.3 and clocks to 4.4 under load. But another one of the windows states the cores have ratios of 37 36 35 34 respectively. This has also puzzled me slightly. Any clarification would be much appreciated.

Edit: Oh, and finally, my BIOS revision is F1. Is it worth updating it? Is all the mention of the risk involved scaremongering?

orby · 12 Jun 2011 at 18:26

i can't help to much as only had my sandy set up since friday, and still experimenting, plus i have an asrock and not a gigabyte but i believe they do require a bios update to get the most of the board, i think i have heard there is an F4 bios

XMP is a profile setting for your ram i believe yours will have it and it just sets them to run at there rated profile, if you want to overclock your ram i believe you want that setting to manual

95 watss is the rating for the cpu at defaults and not sure on the ampage, i dont have those options in my bios

load line callibration i believe trys to stop vdroop when the cpu goes under load it tries to keep the voltage the same at idle to load

the 4 cores ration might be the temps for each core, again dont have that option in my bios

turbo boost is a sorta power saving overclock, at idle it will run at stock but when underload it will go to a maximum of 4.4gig

Phenomenologica · 12 Jun 2011 at 20:54

Thanks for the help.

Can anyone shed any light on the varying voltage figures?

Phenomenologica · 13 Jun 2011 at 20:14

Right well through a mixture of google and educated guesswork I've started having a play. Upped my multiplier to 45 and am now lowering the Vcore to see how low I can get it. At the moment I'm only testing between each voltage drop for about 15 minutes (on prime), I know that's hardly going to root out any minor instabilities but is it alright for getting a rough idea of where I stand?

Once I get to what seems to be a reasonably stable value I'll leave it overnight on Prime95 and see what happens. At first glance though it seems the overclock it came with wasn't exactly optimised! Haven't had a hint of a problem yet and I've dropped the voltage from 1.335 to 1.300, and that's with the core clocked higher. Now to try to nudge it down a bit further. Also, liking the temperature drop. 3-4 degrees cooler on each core now.

Further information: CPU-Z reports that my voltage is slightly lower under load than when idle. Another thread on the 2500k on the first page states that his voltage goes up slightly under load. Any reason for the discrepancy?