Hi guys, I have the same issue, however with 980. I have these random spikes as well (see screenshots) and if I set constant fan RPM, the fan speed fluctuate +/- 200 RPM like crazy and you can hear it, pretty annoying. Can anyone of you try to set duty cycle at 100% an monitor fan RMP in afterburner and check if your fan speed fluctuate? According Palit it is normal, but I don't know. In my previos card when I set a constant fan speed, RMP did not change like this, maybe +/- 10 rpm but definitely not -200....
In any case there is definitely something bad with fans voltage control. I've asked Palit and they've said it is abnormal and I should claim a warranty. So I'm going to replace the card, just a bad luck I would say...
Here's answer from palit about fan start/stop cycle and spikes:
When the fan duty is low the fan might repeat start-and-stop action.
It’s a normal status.
About the short spikes of high fan rpm it’s an abnormal status.
Please kindly contact the store where you bought the graphic card to claim warranty.
Sorry for all the inconvenience this may have caused.
And this they've told me about RPM speed fluctuation:
Yes, it’s a normal status.
The fan can’t fix at specific RPM it will spin around a range near the specific RPM.
The minimum RPM of the fan is about 500, but it has some tolerance (maximum +/- 300RPM).
Also it is not mentioned in all those reviews but Palit has one not very nice feature. They have zero fan mode, that is what we know and it's nice but also a minimum duty cycle when fans are on are about 23% which is around 500RPM. And then they have one ugly feature - instead they will switch off the fans completely below this threshold, they constantly make start/stop cycles for maybe 30 second. I'm asking why ? In my opinion if temp is below 67, they should keep fans running for some time to let the card cool down a bit and then switch them off immediately and not doing start/stop cycles because it is very annoying.
Also this is interesting, look at this graph - you can see the fan start/stop cycle until the card reach 25% duty at about 69C. So from 63C to 69C the card run in start/stop mode which is preeeeety annoying. Imagine that you have an application with low GPU load where the temp vary from 63C - 69C - then you have those start/sop all the time. They should definitely alter a bios so the fan kicks in at 63C right on the 25% duty cycle.... Do you also have such start/stop cycles on your card ?
This is cooling down graph, also at the end start/stop cycles.Edited by misiak - 3/25/15 at 4:24am