Newbie video stuttering question

[Narpoia]

Okay so I bought a new laptop, specs are:

Samsung
Intel Core i7 Processor 2675QM
Windows 7 HP (64b)
6 GB DDR3
AMD HD6750M with 1 Gb DDR5 Ram
1600x900 Screen.

Now I really would have thought there would be no issue with video playback given these internals but there is persistent stuttering when I play AVI and MKV files, regardless which player I use though they vary greatly in the extent of the problem. It is most noticeable during panning shots (To be expected)

First off I updated all the video drivers as I know that the older ones can cause problems. My old laptop was a reasonably ancient Toshiba 2 Ghz Dual core with an AMD videocard that could not handle 720 or 1080 playback but played lower quality AVI files without the smallest hint of stuttering. I have been watching some of the files that worked fine on the old machine with the new one, so I don't think it is an issue with the media.

VLC is the worst, WMP is better and MPC is the best. With VLC the problem is occurs even on the laptop screen while the other two only have real issues when they are projected onto my LED TV. I have installed the AMD system monitor and there is no spike in the GPU or CPU that corresponds with this stuttering and CPU usage doesn't even break 20% when I have 3 different AVI or MKV files running in MPC, VLC and MPC simultaneously. My old laptop would throw some of the same AVIs onto a 50 inch plasma no problem.

I installed the Klite mega codec and while it helped with the higher res files but still has not eliminated the problem. I have not tried with DVDs yet but will do so when I get home today.

If anyone has any advice it would be greatly appreciated.
Thanks

[Chef Goldblum]

Potentially driver issues. May be caused by codec problems as well. The hardware is more than up to the task. Are these newer files that you've downloaded? Have you tried any others to see if it's just these particular files?

[Narpoia]

It is worse in some files than others and does not appear to be more prevalent in newer or older files. I find it so strange that a lot of these files played flawlessly on my older machine using VLC. Really frustrating as I was not expecting to run into issues like this given the hardware. MKV files tend to be better than AVIs.

[Baldrick]

Are you running the laptop in any "power saver" mode?

Stuttering on the tv/hdmi out could be because of wrong display settings. You should try match the HZ to your video source for example. So try different settings in the ati/amd radeon display settings.

[Narpoia]

No I'm running it in performance. Also I have assigned the GPU to the various media players through the Catalyst control centre. I have not tried changing the hz settings, would these also impact the playback on the laptop screen?

[Narpoia]

To make matters worse I just compared the playback of a youtube clip on the PC vs my iPad and it is noticeably stuttering. FML

DVD video playback is flawless, without sound in WMP.

Video and sound is perfect on DVD in VLC.

WTF. Samsung you are not my friend.