Core i7 OC on the Asus P6T (basic) mobo

[AntoFitz]

Hello, I'm quite new to the whole OC thing, I normally just build rigs from scratch as I find it enjoyable and in some cases profitable however I never delved into the whole overclocking thing, now this isn't me requesting an as such "read me" as to how to OC as I know there's plenty of threds on this, its more so a question to experianced OC'ers out there.

I'm interested in OC'ing the core i7 920 on the basic asus P6T mobo to 4.0 Ghz however I'v heard this has an effect on mem and I'v seen cases on forums where people state it dropping ddr3 1600 to ddr3 1033 as such decreasing the effectivness of the ram and increasing the need for diffrent ram, is there a steady way to get this mobo to put out 4.0 Ghz have a 24 hour stable prime and maintain ddr3 1600?

Also with my current rig I'm running an antec 1200 case with v8 coolermaster with a non OC'ed i7 idle at about 27-29 deg C after I OC what temps will I be looking at under full load?

Thanks in advance for feedback.

 

[Meridian]

First of all, don't assume you can get 4GHz, even with water - and certainly not with air. My i920 tops out at 3.8 on that board, for instance, and that is quite common. Some i920s will go further, some will not.


Second, what speed your RAM ends up at depends on what bus speed (Bclk) you end up at, and what RAM divider. In my case I'm on 200MHz, and can set the RAM divider to run the RAM at 1600. But don't worry: RAM speed has no real-world impact on performance, just on a couple of very specific benchmarks.


Temps will depend on CPU voltage: I'm running 1.3875V (higher than some would go) and with the room at 25oC the CPU hits about 79oC running SETI.



OK, overclocking.

The P6T has a number of settings you need to care about:

BCLK
DDR (RAM speed)
UCLK
QPI/RAM Clock

plus the various voltages associated with them.

If you raise BCLK (basically the bus) then the others go up with it. The BIOS will show the new speeds when you set the BCLK speed. Note that UCLK and QPI are shown as data rates, not multipliers as most boards show them.

Generally: UCLCK should be twice RAM speed, and QPI should be higher than UCLK. Note that the board shows QPI at twice its real value: divide by two to compare to what you read elsewhere.

Then you just raise BCLK and wait for things to go wrong. First up will probably be the RAM, so drop the RAM speed down and see if that fixes it. If it doesn't, drop UCLK and try. If it still doesn't work, raise the CPU voltage. Default is 1.20V.

Of course, it's a bit more complicated than that, but that should get you started.


M

(i920 on P6T at 2000 x 19)