So after much cursing I have a stable non-recommended gpu installed in my G20AJ. (MSI Radeon R7950)
I stress the non-recommended as by doing this, your on your own as far as ASUS is concerned, trust me.
I read through a few posts on this forum as well as online and these are the results.
Firstly, to keep it stable I had to reduce voltage down to around 1040mV.
I clocked the card at 800 Core and 1200 Memory stable.
All pretty run of the mill stuff right ?, but here is the kicker!.
I found that the GPU was somehow cutting out when under load.............. couldn't work out why until............ I raised it up away from the HDD underneath by inserting a heat resistant insulated puck.... just those few mm's made all the difference to the stability... Those that know the G20AJ will notice I am not using the supplied cradle, reason being as above, I could not get the card sufficiently away from metal to keep it stable...... I might have this totally wrong if so, let me know please.... anyway she is stable under load furrmark, crysis etc...
Anyhow... if anyone needs help etc either hit me up or see the forum , credit where it's due to WelshGaming as there is some excellent help on her by him.
Finally do you reckon the downclock with the voltage affects performance much ?