Anyway, in that sense I love the KMPlayer for windows. It is built (the main video rendering engine is powered by the opensource mplayer) nicely and has a lots of customizations options + if you want more skins, no problemo, they have hundreds of'em.
Although sometimes the Klite codec pack seem to do a better job while playing the newer H264+ related HD content but if you have an old Laptop (mine is NEC Lavie with intel celeron 1.5Ghz... I'm proud of my PC! :D) or a PC then this setting that I'm going to tell you can speed up those HD video playback by removing some of the CPU load out of your system still without loosing any quality!.
1. First open the KMPlayer and press the "F2" function key on your keyboard.
2. Or, right click on the player and choose -> "options" -> "preference".
3. Then go to "Decoder Usage" from the left side menu and...
4. Choose "Internal Video Decoder".
Look the screenshot below, as my mother onces said "a picture is worth a thousand words" (OK I lied it's a Chinese saying ;-) )....
|Remove that "tick" as shown in number "3"|
5. Then remove the tick form the "H.264" button by clicking on that square box.
After than simply close the window and you're done. So in my experience with my above mentioned CPU, by simply removing this tick, I was able to reduce around 10-17% of CPU usage while playing HD videos. But this simply won't have a huge effect on if you have never powerful Intel or AMD processors but for those of us who are still "stuck" (not by choice ok! errrrrrr), then this might come in handy.
So, that's how my dear users, you speedup the HD video playback in KMPlayer under MS windows.