Choppy HDMI out video...Possible Acer GPU Bios/Driver Issues

I have a 4820TG.
Videos generally run ok over hdmi but slows down a bit here and there.
I tried different decoders and everything but unless i switch the output (in media player classic home cinema) to VMR the problem is there (i need it on EVR but cant get it working with the lag).

Then I noticed that with games, the cutscenes also had the choppiness but actual gameplay was nice and smooth.

So I did a little test and I noticed that during videos the GPU is sometimes clocked down to 100/150.
I think that's why its lagging over hdmi!!
I know its not the CPU because i've set the minimum clocks to 100% and still seen the issue.

I can't read the 6550m bios otherwise i'd try modifying the idle/2D clocks to see if I could get it running smoothly.
Also I can't update to the latest drivers because Acer's proprietary bull!

 

Do you have 2 monitors enabled at the same time? Is Aero enabled?

 

The easiest way of getting around this problem (it's not a solution though) is to use OC software for gaming.
When you force clocks they stick until you reboot or manually revert to default clocks.
When it comes to videos without gaming- use a player that uses hardware acceleration. If WMP doesn't try WMP Classic.

As for driver update- it is possible. Take a look into Owners Lounge for tips.

 

Unless the video file is HD my 5650 also occasionally drops down to 100/150, with HD video it constantly runs at 550/800. Make sure to set the refresh rate to at least 60Hz for the external monitor either in Catalyst Control Center or in Windows advanced screen settings.