I'm running my backup computer as a HTPC, and looking at the specs of it, I should be lucky I'm able to run 720p videos just fine. The main specs below:

P4 Prescott 3.0GHz OCed to 3.7GHz
2GB DDR RAM
Radeon 9600
Asus P4P800-E
Windows 7 Ultimate
Sound Blaster Live 24-Bit (non-EMU10K)
MPC-HC (latest of today)

The TV's resolution is 1366x768, which I used Powerstrip to attain the custom resolution.

So the problem is, I can play 720P videos just fine in windowed mode, but when I switch it to full screen, frame drops are noticeable. Given that I'm able to decode 720p files with no problem, I can assume that the processor is not at fault here, but the video card itself? Would a faster video card improve video playback in fullscreen?

I have a 5900XT and a 9700 PRO lying around; however those cards are power guzzlers and I'm already running an OCed Prescott with four HDDs on a 350W PSU. Do advise.

This post has been edited by colinwong89: Oct 11 2010, 10:08 AM

Managed to partly solve the problem myself. YouTube HD videos must have the Flash 'Hardware Acceleration' setting disabled.