Couple issues... Need help with some troubleshooting

[IC3]

1. My Screen is jumping up and down (Look at the video), this only happens on my Dual-DP cable as when I connected the screen through HDMI everything was fine, same with Dual-DP when refresh rate was set at 60hz. I currently run the screen at 120hz due to my card not bumping up the clocks to 500/1400 (2d clocks) and it idles at 300/150. I have noticed this issue this week after some windows update on monday or tuesday and I also have changed the refresh rate from 144 to 120 as I mentioned above due to my clocks being bumped up. I also disabled the 2nd screen whilst I don't use it and I have changed my drivers from 13.12 to 14.12 (But even whilst reverting the issue persists)

This also happens on desktop... its not just games or any other apps that use fullscreen.

Hardware:

CPU: i5 [email protected]
GPU:HIS IceQ 7950@1050/1400 Modded bios by kahboom - the idle clocks are 300/150 just like the normal 7950 but the voltage has been set to 0.800 instead of the standard 0.900. I've never experienced any issues with this BIOS or card...
RAM: 2x4gb 1600mhz 1.65v
Mobo: Asus P8Z68-V rev. B3
PSU: BeQuiet E9 400w 80 gold


2. Mozilla firefox YouTube videos, once the video starts up after a while the screen goes cream and has greyish stripes.

It was working fine before the firefox update which was rolled out this week... I use chrome anyway so not too fussed about it, but its strange that all of the sudden I these strange problems...

 

[IC3]

So lately what I have changed around in my PC was the following (random order, can't remember exactly what was the exact order):
-Turned off ULPS
-Windows Updates
-I turned off Superfetch/Prefetch via Intel toolbox, checked it in services and its off. I have turned it back on to see if that makes any difference, unfortunately nothing happened.
-AMD Catalyst 14.12 drivers
-Changed my windows refresh rate to 120hz from 144hz and I have disabled my 2 other screens this caused my GPU clocks to idle at 300/150 during desktop stuff, browsing etc.
-2 weeks ago I turned off most of the uneeded stuff in the BIOS which improved my booting times and the system seems to be more stable. I followed THIS guide.

Edit:

I think its the GPU+120hz combination causing these issues, I just tried Mozilla - worked just fine, I tried CS:GO in which I came across some issues, but I got rid of all startup options and its now working. Assetto corsa seems to work as well, this is strange though... I only have had the 144hz monitor for 2 months? I never changed the desktop refresh rate before, but it seems I only have issues when the card is running idle 300/150 with higher refresh rate as once I connect 1 more screen through HDMI this than bumps up the card to 500/1400 and I can set any refresh rate such as 120hz and everything works fine.

Is it possible that the voltage is too low on idle clocks? Should I try to edit the BIOS and get the voltage from 0.800 to 0.900 or will this not make any difference?