gpu speed in sensor tab always alternating

[doctorfate]

My sapphire 4890 toxic is constantly alternating its gpu speed in gpu-z in the sensor tab every second from 960-240,also on the vddc from1.5-4.5,never had or seen this on any ati card i have owned,in ccc it shows present speed at 240 as machine is idling & 960 on scale when in 3d mode,is this bacause gpu-z is very sensitive or is it a possible fault with card,it runs & plays games fine,idles at 38 & 58 when loaded,any one else had similar with any other make of 4890,did not have this on previous card i had which was a 4870 toxic

 

[EGuitarStar]

If I have understood you correctly, this is because the card powers down its processor when it does not need to run at full wack. For example, the GPU does not need to be at 100% to be here on OCUK forums.

This is the same as Intel Speedstep on a CPU.

 

[doctorfate]

perhaps you are right,if thats the case but why dont the core speed show low speed idle ie 2d just like all my previous ati cards & nvidia cards,surly there must be someone who has this constant fluctuating of core speed in gpu-z,if not then there must be a problem with my toxic 4890

 

[bees]

they do that to safe electricity and reduce heat. most likely power and play feature if I'm not mistaken.

 

[titaniumx3]

perhaps you are right,if thats the case but why dont the core speed show low speed idle ie 2d just like all my previous ati cards & nvidia cards,surly there must be someone who has this constant fluctuating of core speed in gpu-z,if not then there must be a problem with my toxic 4890

Did this also on my 4890. If you're on the sensor tab of GPU-Z the GPU will keep jumping to 3D speeds, but once you go back to the first tab, it stops doing it. I think the way GPU-Z detects things causes it to trigger the GPU to jump to 3D speeds.

Nothing to worry about.