285 gtx gpu voltages and ocing

[LORD DAVROS]

Hi guys wonder if someone can help me here.....
I was playing around with NBITOR this week on my new ASUS tops GTX 285 doing the usual oc stuff and got to 702 gpu 1600 shader and 1350 x2 on the mem with out any trouble at all.
At this point I managed to make a silly mistake DOH and flashed the card with an older moded bios from my 280 . I didn't realize what I had done till after I had started fps testing again in occtpt and wondered why the card had suddenly given a jump in fps LOL.
I have put this down to the fact that the 280 bios will allow the gpu voltage to go to 1.18v where as the 285 bios will only allow 1.15. I quickly put the correct bios back into the card but after started to wonder weather it would actually be safe to leave the 280 bios in the 285 card..
The clock /mem/ and shader clocks from my 280 bios were also substantially lower than the oc I had performed on the 285 YET the card was producing around 10 fps more in OCCTPC gpu test.
SO as you might well guess I am now wondering what would happen if I was to put the 280 bios back into my 285 card but use the same clock.mem/shader settings that I currently have .......
Would I get even better fps..... AND would this be safe for the card ?????
the timing settings in both bios's are identical and even the bios revision no.s are the same. But as you all know the 285 will only allow you to run the gpu volt at 1.15 and not 1.18 like the older 280 did..
ANY HELP OR ADVISE WOULD BE WELCOME......

 

[Rroff]

From my experiments the 200 series seemed to overclock better when you reduce temps before they respond to more voltage so increasing the voltage can be counter productive as it increases heat and makes the power leakage problems more likely.

Another thing I've noticed with the 200 series - certain core/shader clock ratios seem to cause worse performance than normal - tho you'd think thats something the manufacturer would have avoided with stock clocks.

 

[setter]

The most i ever hit with my gtx 280 xt (xfx factory oc version) was, 714 on the core,1251 on memory and1512 on the shaders, that was with stock cooling, 19494 in 3dm06 iirc, with a q6600 at 3.8ghz, i havent overclocked the card since, as even at stock at my res of 1920x1200 it plays my games pretty well, just got to get another 280gtx to give sli another run on my new i7 setup.

 

[LORD DAVROS]

Thanks guys. I did do the oc slowly in increments and then check the fps using occtpc and didnt see any drop off points. I did notice that mem and core speed increaces didnt make a lot of difference to the fps.
Also the occtpc test is a total load test and the gpu temp got to about 75c during the test but the fan was able to hold it at that temp running at aprox 98%.

During game play though like in crysis and the new batman game it never got hotter than 65c.

I only ask as in my previous post it was an acident that I put the 280 bios in and with shaders/mem and core speeds lower the fps seemed around 10 or 20 fps higher. Perhaps I will give it another go setting the clock speeds up where they are now and report back

PS. not that it probably makes any difference ... but the card i am using is an asus ENGTX285 top card

 

[LORD DAVROS]

Checked the fps drop off today and didnt see any real drop off between 55c core temp and 75c may be 1 or 2 fps but nothing really notacable.

So does anyone think that if I put the 280 bios back into the 285 card it will cause any problems....

If this works I think it is a beter way of getting a bit more out of it with out soldering bits onto a new card...