GTX980 Clockspeeds keep changing (lower) when at 63 degrees.

[MrHakisak]

hello.
i have an "EVGA GeForce GTX 980 Superclocked ACX 2.0 4GB"

When running unigine heaven (directX-11, ultra settings, v-sync off);
GPU usage is at 99% constant.
GPU Fan Speed 100%.
Temp's get to 63 degrees Celsius.
BUT!!! my GPU clock-speeds go up to 1392MHz until at around 60 degrees -
then it will (automatically) under-clock it's-self to 1380/1366/1342MHz (which causes lower frame rates).

Do you think my card is thermal throttling at 60 degrees?
i thought video cards would thermal throttle at higher temps than that.

PC Specs Below:

Spoiler

i7 2600.
4x4GB Corsair RAM.
EVGA GTX 980 SC.
Asrock Z77 Extreme 4.
850W OCZ 80+ Gold PSU.
Corsair H60 CPU Cooler.
CM Storm Enforcer.
2x Intel 530 120gb SSD
3x1TB HDD's.
Razer Black Widow Chroma.
Razer Mouse Bungee.
Razer Invicta Mouse Pad.
Saitek R.A.T 7 Mouse.
CM Sirus S Headset.
Windows-7 FTW.
@1080p IPS Monitor.

Note the video card is running on PCI-E x16 2.0 NOT 3.0

 

[leigh76]

Its performing perfectly normally. 99% gpu usage is a very good thing.
It changes clocks on the fly.
The changes you are seeing indicates it is working harder when @ 1392MHz, then doesnt need to work as hard when it switches to 1342MHz
Chances are there is less onscreen processing needed at those moments.
If this stresses you out, try MSI Kombuster, the clock should stay constant throughout those tests.
Enable monitoring of GPU POWER too, thats the impressive one to look at with the GTX 980