Very odd indeed!

I've just hooked up my new X800XT to the watercooling system and had a go at overclocking it. With the stock fan, I achieved 552MHz core which obtained a score of 6400 in 3dMark 05.

That's all fine, but when I overclocked the GPU with watercooling, I was able to push it to 606MHz core, before it crashed (still no artifacts beyond that, but I guess the voltage needs to be increased for a further improvement).

With stock cooling, the core temperature exceeded 80ºC at 552MHz
With water cooling, the core temperature never went above 50ºC at 606MHz

After running the benchmark again, it only scored 5,593 in 05 !?!

So 54MHz faster, yet almost 1000 marks lower?

The only thing I can think of is that it's creating errors within the core which is increasing the processing time needed?

Any thoughts?

(memory clock remained the same with both setups...562MHz)

are you able to increase the ram speed? - perhaps the cpu is sat waiting for data from the ram, even though it's processing quicker, it's now waiting for the ram rather than having a constant flow of data from the ram...

Do you mean on the graphics card? Or are you confusing this with the CPU and RAM?
I'm talking about the GPU and the graphics card RAM.

if you mean increase the graphics card's RAM and it'll catch up..Well It's at its max right now but I'll be getting some RAMsinks soon - i'll play around a bit and see what I can do.

Are you sure that you were getting 6400 in the first place? seems bloody high for a slightly o/c'ed x800XTPE on a graphics-only dependant benchmark.
My X850XTPE at 620/600 gets only 200+ more and that would be considered resonably normal points/clockspeed ratio.

So assuming your original result was around 5400, then 5593 would seem almost exactly what you should be getting after a 54mhz increase; 150-300 points - based on the fact my core increases by about 500 for a 80mhz increase.


More voltage should get you to 650mhz+ but watch temps, 50c isgetting a bit hot for water.. the VID mod is the easyest for gpu voltage, I would say rise it to 1.5-1.6.

Quote:

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Originally Posted by hwAnalyst

Do you mean on the graphics card? Or are you confusing this with the CPU and RAM?
I'm talking about the GPU and the graphics card RAM.

if you mean increase the graphics card's RAM and it'll catch up..Well It's at its max right now but I'll be getting some RAMsinks soon - i'll play around a bit and see what I can do.

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yeah sorry i did mean the GPU when I put cpu.

http://service.futuremark.com/compare?3dm05=956151 That's my score...I used PowerStrip instead of ATI Tool and managed to increase the clock speed to 596MHz without it decreasing in performance. Anything higher and it goes back to the 5xxx scores.

I've never done Vmodding before, I might give it a go though. Any recommended links where I can read up on how to do it for the X800XT?

The cooling is a modded water dispenser water-chiller which cools the water down. It seems to be keeping my OCed CPU at 25ºC and the graphics card at 50ºC (It has a thermostat). The core frequency doesn't seem to affect the temperature with this setup, although I'll be adding another compressor to the setup shortly to reduce the temps further.

After adding RAM Sinks to the RAM, I was able to set the core clock to 600MHz and the RAM to 591MHz. This has enabled me to reach a score of 6826 in 3DMark05.

Thanks for all your feedback and advice, I appreciate it.

Link: http://service.futuremark.com/compare?3dm05=961470

Well im suprised your getting uch high scores, nice.

The VID mod is probably the easyest/requires least skill. If you read through this you should have a good idea of how its done. http://forums.techpowerup.com/showthread.php?t=2184

Whats the wattage rating of your waterchiller?
I thought that kind of chiller were all TEC based, I didnt realise they had compressors. Got any pics of it?