Bit of OC help appreciated...

[tickleonthetum]

OK, I've got my i7 920 OC'ed on my Asus P6T Deluxe V2 like so:

CPU Ratio: 21
BCLK: 191
CPU Volts: 1.29375
CPU PLL: 1.82
QPI/DRAM Core Volts: 1.35000
DRAM Bus Volts: 1.66

However, I have 6Gb (3x 2Gb) Corsair DDR3-1866MHz 9-9-9-24-2T memory which at the settings above runs at 1531MHz. So I tightened (if that's the right term) the timings to 8-8-8-22-1T.

Now this gives me a CPU Speed of 4011MHz (or 4.0GHz) which i am happy with. The temperatures are:
Idle: 34C (average)
Load: 69C (Average)

All is stable in Prime95, IntelBurnTest2.3 & OCCT.

What I'd like to know is, is there anything I can do to give the memory more of a boost? I don't understand all the technical jargon so please explain what it does if you offer changes to make. I would like to keep my temps as low as possible (<70C if poss.) and my CPU at 4Ghz or higher. The PC is used for everything from emailing to 3D rendering, from Word Processing to hardcore Gaming...

[matty-hodgson]

the maximum DRAM voltage for the i7 is only supposed to be 1.65v. i dunno how safe it is to be 0.1v over that.

does the memory really need a boost?
try turning it down 15% and run a benchmark either side of the adjustment and if there's a difference then maybe OC'ing it will help. but i'd do that first.

[ta2]

I don't think you'll get much, if any, boost from having a higher memory frequency. You're already running triple channel 1531MHz.

Are you sure you need your QPI voltage at 1.35v for that overclock?

[tickleonthetum]

the maximum DRAM voltage for the i7 is only supposed to be 1.65v. i dunno how safe it is to be 0.1v over that.

does the memory really need a boost?
try turning it down 15% and run a benchmark either side of the adjustment and if there's a difference then maybe OC'ing it will help. but i'd do that first.

The MB only allows 1.64 or 1.66 and according to all the sites I've researched 1.66 should be OK.

I don't think you'll get much, if any, boost from having a higher memory frequency. You're already running triple channel 1531MHz.

Are you sure you need your QPI voltage at 1.35v for that overclock?

I haven't a clue! The MB by default set it to 1.66666 and it was only by searching the Net that I found out that it could be lower! I don't know what the correct default is.



I am thinking of increasing my BCLK by 1 step at a time and see if I can improve to CPU overclock a bit. Does this sound like a better idea than trying to get the memory any faster?

UPDATE 1
=======
Leaving everything the same and just raising the BCLK, 193 is the highest I can get, anything higher and it BSODs. Even when it BSODed Core Temp reported a mximum of 71C, so I don't think heat is a problem...

UPDATE 2
=======
Found this test of memory speeds and timings (http://www.tomshardware.com/reviews/...ests,1807.html) and the results suggest that there is no real world noticeable difference seen between memory settings. So I think if I do any more tweaking it will be to get the CPU speed higher without major heat increase. Any suggestions on that?

[ta2]

I think your voltages are far from optimal. I'd chuck them all down to minimum, except the VCore at 1.29375V and DRAM at 1.65V. 4GHz is not a crazy overclock so you shouldn't need to raise the others, certainly not as much as you have.

That link you gave regarding the memory is out of date. Lynnfield and Bloomfield have completely different memory characteristics. As for what I said before, you don't need to increase the memory frequency, but might benefit if you could get them down to CAS7 (perhaps lower the frequency a little bit even, if you can still get 4GHz by doing this).

Oh... oops. Forgot to mention this only applies to the D0 stepping, you might need those high voltages if you got a C0 i7 920.

[tickleonthetum]

I think your voltages are far from optimal. I'd chuck them all down to minimum, except the VCore at 1.29375V and DRAM at 1.65V. 4GHz is not a crazy overclock so you shouldn't need to raise the others, certainly not as much as you have.

CPU PLL: 1.82 <--- Seemed to need this little bump up to keep stable.
QPI/DRAM Core Volts: 1.35000 <--- This was based on a Net search, as Asus had it default to 1.6000

Every thing else, other than what I have already mentioned, is on Auto.

That link you gave regarding the memory is out of date. Lynnfield and Bloomfield have completely different memory characteristics. As for what I said before, you don't need to increase the memory frequency, but might benefit if you could get them down to CAS7 (perhaps lower the frequency a little bit even, if you can still get 4GHz by doing this).

I didn't realise the i7 DDR3s were so different. What do i7 X58s prefer? Higher MHz or lower Timings?

Oh... oops. Forgot to mention this only applies to the D0 stepping, you might need those high voltages if you got a C0 i7 920.

Yes, I have a D0.

[ta2]

I didn't realise the i7 DDR3s were so different. What do i7 X58s prefer? Higher MHz or lower Timings?

Lower timings.

[tickleonthetum]

Lower timings.

Thanks...