Sub-ambient watercooling - help needed with overclock

Stan_Lite

Stan_Lite

Stan_Lite

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Good morning.

Bought myself an aquarium water chiller for some extreme watercooling. The cooling system is working like a charm with considerably lower temperatures than standard watercooling.

I'm having trouble with the overclock though. I bought myself an i7 950 in the hopes of getting a stellar OC but I'm struggling with it - problem is, I can't get to grips with i7 overclocking. It's taken me two days to get a stable OC at 4.4GHz. That's with a vcore of 1.55V and QPI/VTT voltage of 1.45V - all other voltages are on auto (basically because I don't know where to start with those). At the moment, I'm on a 21 multiplier and a BCLK of 210. I've tried various combinations of multiplier and BCLK to get higher with vcore as high as 1.6V and QPI as high as 1.55V with no success.

System spec:
Case - Akasa Eclipse 62 (had this for 5 years and still love it).
MB - Gigabyte EX58 UD3R
CPU - i7 950
RAM - OCZ Obsidian 6GB (3x2GB) DDR3 PC3-12800C9 1600Mhz Triple Channel Kit
GFX - Powercolor HD 4890

Cooling:
Chiller - D-D DC750
Pump - Swiftech Laing D5 Vario MCP655
CPU block - Heatkiller 3.0 LT
Res - XSPC single bay res
Tubing - 1/2" black XSPC
Fittings - EK Polished Nickel Plated Brass G1/4" (BSPP) Thread to 1/2" Hose Tail

I would like some suggestions from anyone who has been higher. I suspect I may get more if I fiddle with other voltages/settings but I really don't know where to start. Any help would be appreciated.

I'll be a bit miffed if I can't get higher than this - I suspect I could have got the same OC with the 920 I replaced with the 950.

For information, CPU temps at current OC/voltages are 28-30C idle and 58-60C under load with water temperature set to 15C. I can reduce the water temperature to about 10C without causing condensation so further cooling is available.
Also, I managed to bork my GTX295 when I fitted the waterblock. I was very careful and wasn't aware of doing any damage but, when I went to boot up, I got the beep code for faulty graphics :( I've stuck in a 4890 to tide me over for now. It was always my intention to stick a couple of WC'd GTX460s in there but I'll be gutted if the 295 is ruined - it was a cracking Folding card.
 
Ram voltage and multiplier?

Ram should be at 1.6-1.65V in my opinion with 8x 210 = 1680MHz or 6.66x 210 = 1400MHz until the max OC is reached on the CPU.

PCIe locked at 100MHz?

andy.
 
that board will be holding you back

what kind of pll are you using, and what memory speed are you running?
assuming 1600+ at 210 blk? then that OCZ will be causing the issue.

if the imc on the cpu isnt great then you may get trouble too
 
nkata said:
Ram voltage and multiplier?

Ram should be at 1.6-1.65V in my opinion with 8x 210 = 1680MHz or 6.66x 210 = 1400MHz until the max OC is reached on the CPU.

PCIe locked at 100MHz?

andy.
Click to expand...

RAM voltage is on auto at the moment but I've had it on 1.66V for much of the time and it makes no difference. Multiplier is 8X - again, I had it at 6X for most of the time I was experimenting but still no difference. I only put it up to 8X once I realised I wouldn't get any further with the OC.

PCIe is currently at 101MHz.
 
Stan_Lite said:
What would you suggest as a replacement?
Click to expand...

errr, well i personally wouldnt suggest changing your board for a 200mhz gain

to get the flexability then you would need a board aimed at overclocking, but then you would maybe be presented with something that probably wouldnt clcok much different to the ud3r

are you clocking the cpu with the memory at rated speeds or have you taken it right down to eliminate it from the clock?

personally i would keep the ud3r if it is churning out 210bclk
 
rjkoneill said:
errr, well i personally wouldnt suggest changing your board for a 200mhz gain

to get the flexability then you would need a board aimed at overclocking, but then you would maybe be presented with something that probably wouldnt clcok much different to the ud3r

are you clocking the cpu with the memory at rated speeds or have you taken it right down to eliminate it from the clock?

personally i would keep the ud3r if it is churning out 210bclk
Click to expand...

Normally, I wouldn't consider spending money on a new board for a few extra MHz but I will be using the old 920 to make a new system to replace one of my ageing Q6600 rigs so would be buying a new board anyway. If I can get a bit more from another board, I'll get that and put the 950 in there to get the most from it and put the 920 back in the UD3R in the new system.

I was clocking with the memory on a 6X multiplier and slackish timings and only put it back up to 8X when I reached the max stable OC.
 
in that case

consider a rampage II

it has all the same features as a rampage III bar usb3 and sata 6 [both are pointless imho anyway]

its a premium overclcoking board and is far cheaper.

i wouldnt touch another gigabyte unless you look at UD7 [£££] otherwise you would be just as well keeping the ud3r
 
That's the one I was looking at.

I like Gigabyte boards and for overclocking on air, they're perfectly fine. I've read many good reviews on the Rampage so I think I'll give it a go. As I said, I would have been buying another board anyway so I may as well give it a go - see how I get on.
 
that would be my choice.

im moving away from mine to a UD7 in the next few weeks but the ramapge has been a solid board for 18 months for me now

makes overclocking very easy.

also, there is a very informative thread on Xs about it where high clocks are aplenty
 
Thanks for that. That's a massive thread, I'll have a good read of that between now and when the board arrives tomorrow :D
 
no worries

if you have any problems then give me a shout. i know the rampage II inside out and have experienced just about every little niggle it has to offer.

word of warning. there is a new beta bios out for it. [1903 iirc]
dont use that, use the 1802 [it should ship with that bios anyway] as it has been solid for many users.
 
The Gigabytes tend to crap out about 210-215 bclk. My UD5 won't play ball over 212bclk. There are a few things you can try like raising the pcie to 102-103. Other than that you are limited to hard modding the board to gain more PCIe which is rumoured to help the bclk.
 
w3bbo said:
The Gigabytes tend to crap out about 210-215 bclk. My UD5 won't play ball over 212bclk. There are a few things you can try like raising the pcie to 102-103. Other than that you are limited to hard modding the board to gain more PCIe which is rumoured to help the bclk.
Click to expand...

Mine is roughly the same. I did get it to boot at 215 but couldn't get it stable. I was hoping the higher multipliers on the 950 would help me get higher but, alas, no joy. Hopefully the Rampage will allow me to get a bit more out of it.
 
Try QPI/VTT at 1.75 and Vcore at 1.45 see if you can get it going at that, don't go over 1.8 on the QPI/VTT and you may even need to drop vcore down to get it stable to 1.35 or less.

The trick I have found is QPI voltages.

Yes Pci to 102/103, also PLL at 1.85
 
Biffa said:
Try QPI/VTT at 1.75 and Vcore at 1.45 see if you can get it going at that, don't go over 1.8 on the QPI/VTT and you may even need to drop vcore down to get it stable to 1.35 or less.

The trick I have found is QPI voltages.

Yes Pci to 102/103, also PLL at 1.85
Click to expand...

I'll give that a bash later - Thanks Biffa. I was a bit dubious about going too high on the QPI since Intel recommends no higher than 1.35. I figured they'd be conservative with it so I was happy to go to about 1.55 but wasn't aware it would be safe to go as high as 1.75.
 
Watching this with interest as although I don't have sub ambient cooling I am also trying to overclock my 950.

Currently at 4Ghz with vcore 1.25v and QPI/VTT of 1.30v. Auto had put it on 1.8v which scared me at first.
 
Hey Stan, hope I haven't buggered up your system :)

I meant 1.375 - 1.38 on the QPI

I'm currently running 1.325-1.375 depending on which machine I'm running on. (bet you can guess which ones is the highest)
 
Biffa said:
Hey Stan, hope I haven't buggered up your system :)

I meant 1.375 - 1.38 on the QPI

I'm currently running 1.325-1.375 depending on which machine I'm running on. (bet you can guess which ones is the highest)
Click to expand...

Thought it sounded a bit high :p

I was already running it at 1.45V to get it stable at 4.4GHz. I did push it up to 1.7V briefly but even that made no difference. No damage done.

My Rampage should be arriving this afternoon - should've been delivered yesterday but apparently DPD had 20 drivers off sick in my area yesterday. Must have been some sort of epidemic. Once I get that put together and Windows installed, I'll have a fun evening seeing if I can squeeze a bit more out of it.

I'll report back once I've had a good play.
 
rjkoneill said:
that would be my choice.

im moving away from mine to a UD7 in the next few weeks but the ramapge has been a solid board for 18 months for me now

makes overclocking very easy.

also, there is a very informative thread on Xs about it where high clocks are aplenty
Click to expand...

Why are you switching from a rampage ii to a UD7 if you dont mind me asking?
 
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