GUIMiner - openCL and setting lower memory clock for AMD radeon graphics cards

[palmiris]

The guiminer has a problem with choosing the correct memory clock when using an AMD Radeon graphics card (7750).

For example I am setting memory clock of 700 in overdrive (AMD radeon 77XX latest driver) in order to lower my gpu temperature. My graphics card supports 1125mhz.

Guiminer instead of utilizing 700, which I already set it as the maximum in overdrive, it utilizes 1125 which is the designed graphics card memory clock.
If I overclock memory it uses the overclocked memory, eg 1200. If I underclock below 1125 it stays 1125.

Is there a way to either:
1. Utilize the user overdrive memory clock set by the user instead of the graphics card supported memory clock or
2. To use an extra flag to set a lower memory clock

The gpu-z sensors tell that I am using a GPU Memory Clock of 1125MHz. This only happens with guiminer. With other applications the max memory clock stays at 700MHz as selected from AMDs overdrive app.

I need to lower the temperature without loosing performance thus I need to set the GPUs memory clock lower than 1125MHz, but guiminer does not allow it. Please help

Thanks

[palmiris]

Hello,
This problem is solved with crimson driver 16.3 released today 10/3/2016, so it is not a problem of GUIMiner, rather it was a problem with the AMD radeon HD7750 driver, and all previously releases. Temperature has fallen from 55 to 51. I did send a problem report to AMD and they seem they corrected it immediately. 700mhz is the lowest setting for memory clock. Below this value it is going to default which on my case is 1125mhz.

[Koltan]

I've got the similar problem on HD7790 and all drivers from 14.9 to 16.5.2.

I set memory clock underclocking. But when I start sgminer, the clock returns to 1600MHz, no matter what value I set in Afterburner or AMD Settings.

It looks like driver has three different types of clocking: 2D, 3D and separate clocks for OpenCL.

If I install driver versions 14.4 or older, underclocking works perfectly, but the mining speed on these drivers is very poor.