I've managed to get rid of the artifacts, caused by low voltages at idle - just as everybody's been saying, an increase to the 2d idle clock is all that's needed. Increasing the 2d memory clock ever so slightly increases voltages, eliminating the issue of artifacts appearing.
The way i have things set up is, *(Ati overdrive must be enabled in CCC)
In C:\Users\yourname\AppData\Local\ATI\ACE\profiles.x ml file i edited
<Feature name="MemoryClockTarget_PCI_VEN_1002&DEV_6798& amp;SUBSYS_27701462&REV_00_4&5581F2C&0 &0038A">
<Property name="Want_0" value="15000" />
<Property name="Want_1" value="156500" />
To read..
<Feature name="MemoryClockTarget_PCI_VEN_1002&DEV_6798& amp;SUBSYS_27701462&REV_00_4&5581F2C&0 &0038A">
<Property name="Want_0" value="65000" />
<Property name="Want_1" value="156500" />
This gave the 2d clock, whilst idle, a much needed bump to increase idle voltages to 0.949v, (a bit high on the voltage side - resulting in higher heat, but if you so wish you can try reducing the memory clock from 650mhz to 450mhz, hence reducing the volts, and see if that resolves the artifacts, if not, increase the clock further. 650mhz does it for me.
In afterburner, I decided I wanted the default 1010mhz/1375mhz/1.174v to be higher, and give my 7970 a semi decent overclock. I found things to be stable at 1100/1565/1.187v (with unlocked volts in afterburners settings) along with LtMatt's custom fan profile to keep things cooler. I saved the settings to profile 1, apply at startup is ticked.
After rebooting, Ati overdrive adjusts the 2d clock, increases it from 150mhz to 650mhz, as set in the cfg, and sets the fan profile to auto or manual as specified in CCC Overdrive, overdrives fan settings are limited as you can't actually set a curve like you can in Afterburner. The plan is to use Afterburners fan profile. But sometimes it doesn't work. At startup, both Afterburner and Ati overdrive load together, and whichever loads last sets the fan profile. In my case overdrive would load last.
So to fix that I added a delay to Afterburner's startup, you can find the cfg file here - C:\Program Files (x86)\MSI Afterburner\MSIAfterburner.cfg
Look for the line StartupDelay = , and adjust it so that it reads 10000.
Save the cfg file and overwrite. If you receive an error, , be sure to change the file type to "all files" and not "txt document" and save it to your desktop. Copy the file from your desktop into the Afterburner folder and overwrite, it should work this time.
Reboot.
Now Ati overdrive takes care of the 2d clock, 150mhz > 650mhz - fixing the idle corruption/flashes/flickering etc.
Afterburner 2.2.5 kicks in shortly after and applies the 3d clock with custom fan profile. Both work in harmony.
Worth mentioning, at all times the memory voltage is reported at 1.600v. Only the core voltage seems to increase/decrease in relation to the memory speed.
