HD6790: can't downclock mem nor undervolt gpu

[Qu4k3r]

I have a rig with 3 vcards:
2x6790
1x5830

5830 can be downclock ram to 300mhz + undervolt gpu to 1.05v @870/300 successfully.

But it can't be done on 6790's, I want to do it in order to reduce stress and temp on their vrm but no succeed.

I tried with several driver versions for win7 x64 (11.1, 11.12, 12.1) using cgminer, and also tried linux BAMT.

Don't matter what ram freq nor what gpu voltage I set, they seem to be locked to 1050mhz and 1.19v

Any idea?

Thanks in advance  

[scifimike12]

Try using MSI Afterburner.  Edit MSIAfterburner.cfg using Notepad and change UnofficialOverclockingMode = 0.  When you launch AB, click accept, and then try lowering your memory.  Then close AB and then launch it again.  Rinse and repeat until you get down to your desired value(s).

[Qu4k3r]

I tried AB before but all clocks showed "0" and couldn't change freq.

So I tried again and checked dummy plugs and I found the problem, resistor was a little bit loose.

Now both 6790 are set to 300mhz on ram, so gpu temp decrease 6~7ºC and VRM temp decrease 10ºC

gpu vddc still seems locked to 1.19v but I guess there is no need to get it lower.

Thanks a lot!!!