8800 GTX Shader clock + Voltmod?

[[XC] riptide]

I'm finding it very difficult to find out what improvements I'd get with a vmod on the shaders. I have a 8800 GTX at 1836 shaders<<not entirely stable and I'd like to know if anyone has any experience with with this card and shader stability with Mods. Stock cooling, but cool ambients and plenty of fannage keep it <80C. I bumped up an old thread in teh Vmod section asking but nobody loves me..

[coo-coo-clocker]

Rip,
to unearth an old thread, but what ever came of this?
What shader did you settle in on for the 8800GTX?
How hot is "max hot" for this thing?

[[XC] riptide]

coo-coo. Settled with 1729 shaders. Next stop is 1836. Too much on this old G80. Never bothered with the VMOD as that would automatically mean MOAR cooling. And I ain't gonna spend $$$ cooling a 2 year old tech.

[OldChap]

I've never volt-modded but have observed that the various overclocks, as you move toward the top end of a card's possibilities, each have a temperature limit

Midwinter, and ambient temps at around 5 deg would allow me to run my gx2's with the big fanmod at 1944 on the shaders with temps below 60deg stable...as ambient temps rose and the card temps went through 67 deg then it became more and more unstable til it became necessary to reduce clocks by a step. At 1890 the limit was again found when ambients took the card temps to 74 deg. midsummer ambients here are not often over 28-30 deg and require that shaders are reduced to 1836 when card temps mostly allow folding at <80 deg.

If PG would allow us to select the type of WU downloaded we could get a shed load more work done in summer as the overclocks would be for cooler running

Not much of an answer to your question but perhaps pertinant info nonetheless

[[XC] riptide]

I've never volt-modded but have observed that the various overclocks, as you move toward the top end of a card's possibilities, each have a temperature limit

Midwinter, and ambient temps at around 5 deg would allow me to run my gx2's with the big fanmod at 1944 on the shaders with temps below 60deg stable...as ambient temps rose and the card temps went through 67 deg then it became more and more unstable til it became necessary to reduce clocks by a step. At 1890 the limit was again found when ambients took the card temps to 74 deg. midsummer ambients here are not often over 28-30 deg and require that shaders are reduced to 1836 when card temps mostly allow folding at <80 deg.

If PG would allow us to select the type of WU downloaded we could get a shed load more work done in summer as the overclocks would be for cooler running

Not much of an answer to your question but perhaps pertinant info nonetheless

Exactly! I live in East Coast Ireland. You live in South Coast Blighty, maybe 200 miles south of my latitude. Our temps at the height of summer MIGHT be 26-27. Anything more is a heatwave, and the pint goes flat faster.... in which case its a national emergency. Today for example its about 18C and will be between 16 and 21 for the rest of the day.

But yes temps are really limiting. BUT on a 8800GTX.... you do need volt mod to get to 1836+ stable regardless of temps. The next step, 189x, on idle would crash. Thats idle temps of ~50 maybe.

My question originally here was what shaders would I get more out of a voltmod. I might get 700+ Core CLocks with a voltmod, but shader clocks are not that well documented. IN fact most of what I have read pointed that I'm already near the limit of shader clocks.... Voltmod or not.

[OldChap]

Based on the above observations maybe the question is......rather than a voltmod which would increase temps. would more extreme cooling allow increased shader clocks? (cannot answer...... chill box not ready and don't have any gpu's under water yet)

[coo-coo-clocker]

Good info - thanks.
Did you guys ever find that there was a necessary link between shader clocks and core or mem clocks? Did it help to improve stability by adjusting core or mem clocks as you raise shaders? If it is simply a matter of core temps that are tied to stability, is it possible to lower core or mem clocks to reduce heat, even while increasing the shaders?

[[XC] riptide]

Good info - thanks.
Did you guys ever find that there was a necessary link between shader clocks and core or mem clocks? Did it help to improve stability by adjusting core or mem clocks as you raise shaders? If it is simply a matter of core temps that are tied to stability, is it possible to lower core or mem clocks to reduce heat, even while increasing the shaders?

Well... I'm not sure about adjusting cores with shaders to effect stability. BUT what i do know is, due to the stepwise nature of Core and especially shader clocks... I found that if I could bring down core clocks I could increase shader clocks by a step or two. Now... we know that core clocks do have an effect on the PPD.... but not as much as the increase in PPD I was able to achieve by the associated increase in shader clocks. Running temps diff between my core at 400 or 594 made a 4-5C difference. A 4-5C difference could mean another step in shaders (and did in my case) which more than compensated in PPD.

As for overall stability, I do know that increasing the PCIE clock in the bios does give you a few Mhz celing in stability. Not much... but some... as much as I can see from the 3dmark boys... and IIRC this applied especially to memory clocks.