An attempt at 980Ti overclocking

With the watercooling installed and running... of course I need to try stressing it.

For now I'm focusing on a 980 Ti, originally an Asus reference blower version.

Only increasing core clock, the highest stable I've run so far is 1447 (+270 setting) without touching voltage. 1457 seemed ok at first but threw a wobbly later. This has ran Heaven for a while and done a loop of TimeSpy, and now I'm leaving it to cook on FireStrike. This could be my new 24/7 running state if proven stable.

Next I guess I should see what it does with some voltage...

Ok, at the previous settings FireStrike stress test went fine. It then failed TimeSpy stress test.

Let's try some more voltage then. At the same clock as before, just increasing the voltage let it boost a bit further to 1470-ish. Let's try +300. Nope. Insta-crash. So, 1500 doesn't seem possible to clock. Is the wall that steep? With the slider all the way up, I neglected to see what it went up to, but got at least 1.23V. That didn't seem to buy me much more core clock at all. If I understand correctly, at this point I'd need a bios mod to unlock higher voltages.

I checked the ASIC quality in GPU-Z. 64.1%, which was higher than 4.5% of similar cards. Have I lost the silicon lottery here? Does it make any difference anyway? That is, has anyone correlated the ASIC quality with overclocking potential?

Right now I'm soaking at +250 core for 1427 at stock volts. I'm still interested in a stock voltage 24/7 overclock. I could also play with the ram speeds next.

Ok, looked again at voltages. At stock or +250 core, it runs Heaven at 1.199v. If I increase the core voltage, that goes up to 1.23 and after that doesn't go up further. So, basically not really much of an increase and thus not much more on the core clock. Not enough to break 1500 anyway.

Let's see......

Are you hitting the power limit on the card?
ASIC quality is MEH... most cards are hitting on the bell curve of 1500 Mhz give or take 25 Mhz or so. So you end up where most end up.

Card isn't reporting power limiting, not with Heaven anyway. That was only around up to 100% mark overclocked. I relaxed to 110% in case and that made no difference. Question then is, how much further could I expect for how much more voltage if I were to bios mod?

I have a custom VBIOS on my Zotac AMP Extreme 980Ti. It regularly throws out Pwr, VRel and VOp in the GPUz PerfCap monitoring all at once but doesn't throttle. I know the voltage tables, boost tables and power tables have all been altered in this VBIOS.

mackerel said:

Card isn't reporting power limiting, not with Heaven anyway. That was only around up to 100% mark overclocked. I relaxed to 110% in case and that made no difference. Question then is, how much further could I expect for how much more voltage if I were to bios mod?

Click to expand...

The highest overclock I've ever read about for a 980Ti is 1600MHz on overclock.net under water.

As ED said 1500 MHz should be doable, although on air it could get pretty toasty. I'm hitting 1480 Mhz on my 980Ti w/a VBIOS modded to 1.256V but is indicated as being 1.261V in GPUz and PrecisionX.

I've read that Vcore voltages of 1.28 are workable on Maxwell 2, but I haven't verified that.

To recap, where I'm at now is:
1427 appears stable at stock 1.20v (TimeSpy, FireStrike, Heaven)
1447 is unstable at stock 1.20v
1470+ seemed ok in a quick look at 1.23v but not further tested.
1500+ instant crashes at 1.23v.

Voltages are card reported. I can't set above 1.23v. Temps are great with the water cooler, has remained well under 40C under current testing loads. I just wonder how much more could I get if I mod past the 1.23v mark. Haven't tried ram yet.

I think you reached the wall and you won't get any extra by adding more volts...