GPU clock speeds lower than they should be

[Barnaby1000]

My core clock and memory clock speeds for my radeon hd 7870 are running at 925 MHz for my core clock and 435 MHz for my memory and this is affecting my frame rate giving me sudden drops from time to time and running GTA V at 30-60 FPS. i know this card should be running at 1000 MHz core clock and 1200 MHz as stock but even increasing the clock speeds in the latest version of MSI afterburner isn't affecting the clock speeds or frame rates in any way. i have another radeon hd 7870 GPU but that has problems of its own and is made by a different card manufacturer but that is getting the base clock speeds it should be doing in-game on GTA V and is giving 46-87 FPS with the same settings and drivers. updating drivers doesnt seem to help and the same goes for updating MSI afterburner and im now out of ideas that could possibly help. does anyone have any ideas or suggestions or maybe knows how to fix this? any help would be appreciated :-)

[Barnaby1000]

about 55 degrees Celsius 

4 minutes ago, rrubberr said:

From my experience with the 7900 series, you're lucky if you stay away from the max clock. That way it keeps below 100 degrees. In all seriousness, though, what are your temps?

 

[Barnaby1000]

3 minutes ago, rrubberr said:

Was the card normal up until recently, or has something changed? CCC also has some overclock controls of its own I think.

It has been like this since about a week after i got the GPU. but even attempting to overclock is seeming to not change a thing.