Perplexing OC'ing situation! Radeon 7950 OC = Lower FPS

This is the situation,

I load up GTA V, I got a specific spot in the club, and I get 85 fps, rock solid. Great, okay!

I turn on afterburner, turn up the power limit by 10%, and my boost clock becomes more stable, usually staying at 925, and I get 88 FPS. I undo this, and it returns to 85 fps.

I turn up Core clock 100 Mhz, and I drop down to 65-70 fps. My core clock frequency is bouncing all over the place! So, undo that, and set it back to 925. Solid 85 again.

I turn up VRAM +100 MHz, and again 65-70 fps. I undo it, and again rock solid 85 again.

I try a mix of the three, and the outcome is always the same, a drop of about 20% fps.


So, I tested it in the Witcher 3, and it was the same outcome.


So, I thought, maybe the Radeon Crimson settings were screwing up Afterburner. So, I did the OCs in Crimson, same outcome!


What is going on here?!

Sounds like an unstable overclock, try working up by 25mhz increments and see where the instability occurs.

I would assume that as well, but just an increase of a 100 Mhz is unstable!? That seems a bit insane! I will give it a shot though, thx.

Do you think it might be this old ****ty PSU? I also have a xeon x5650 with a bclk of 185 running atm.

Could be. Did you try increasing voltage at all and are your temperatures in check?

I haven't tried increasing voltages, because I wanted to take it kind of slow, as I am a complete amateur at OC'ing stuff. I have tinkered with PCs for 20 years, but OC'ing was never something I was particularly interested in, as I wanted to ensure my components lasted as long as possible.

I increased the Core clock by 25 MHz while in game, and it did the same thing.

I reduced it by 25, and it dropped the FPS down to about 81 fps.


The core clock jumps around like crazy when I change the memory speed too!


This PSU is like 6 years old. I have a multimeter, maybe I should test it?

If you can list the full system specs that would help, I'll list mine as an example.

I5-4690k
Gigabyte Z97X SOC Force
2x4gb Tridentx 2400 ram
2x - XFX hd7970
EVGA G2 750w psu
Cpu and GPUs under water

- - - Updated - - -

Something does not seem right did you update any drivers recently?

Lochekey said:

If you can list the full system specs that would help, I'll list mine as an example.

I5-4690k
Gigabyte Z97X SOC Force
2x4gb Tridentx 2400 ram
2x - XFX hd7970
EVGA G2 750w psu
Cpu and GPUs under water

- - - Updated - - -

Something does not seem right did you update any drivers recently?

Click to expand...

Xeon x5650 BCLK OC 185
MS-7591
12gb 1600 Mhz Memory, clocked at 8*185=1480. I don't think xmp is enabled, so I think it might be running effectively at 1333.
7950 Boost
Air cooled

I think I updated the GPU driver recently, but that's it.

I would check your 12v rail on your PSU.

I fixed it. Changing the speed at all was forcing boost voltages, I think, and it somehow made it unstable. I had a feeling that my boost speed hasn't been working correctly for awhile now. It was never stable at 925, it's been jumping up and down like crazy between 850 and 925. I thought it was **** drivers for a long time, and I didn't know they increased the voltage for boost.

I increased the power limit by 20%, decreased the boost voltage from 1.25, and it seems to be stable at 1.15v 1050 Core 1500 memory.

It's almost hard to believe it's nearly 20% faster at a lower voltage than the boost.


Max temp in Valley was 76, which seems a bit high, but I have seen it get to 75 before at stock. Do you think cleaning it, and adding new thermal paste would be worthwhile?

mysticjbyrd said:

I fixed it. Changing the speed at all was forcing boost voltages, I think, and it somehow made it unstable. I had a feeling that my boost speed hasn't been working correctly for awhile now. It was never stable at 925, it's been jumping up and down like crazy between 850 and 925. I thought it was **** drivers for a long time, and I didn't know they increased the voltage for boost.

I increased the power limit by 20%, decreased the boost voltage from 1.25, and it seems to be stable at 1.15v 1050 Core 1500 memory.

It's almost hard to believe it's nearly 20% faster at a lower voltage than the boost.


Max temp in Valley was 76, which seems a bit high, but I have seen it get to 75 before at stock. Do you think cleaning it, and adding new thermal paste would be worthwhile?

Click to expand...

Whenever I buy a used gpu I completely disassemble it, clean it and reapply the tim. If it has pads I apply tim instead instead of using the pads.