ok guys its me again, and lately I been convering Megadeth songs, especially Holy Wars and Tornado of Souls. They use a lot of power chords in rhythm. I find playing power chords fast real difficult. I am confused> Do u DOWNPICK all 3 or 2 strings very fast? or ALTERNATE PICK 3 or 2 strings, like strumming? if i downpick the 4th 5th and 6th strings, it puts pressure into my hand and I can't keep up for long time..and if i alternate pick, sometimes I don't hit one ot two string...which is the correct method for fast power chord switching n playing (rhythm)? both? just practice?
ALSO, the tab shows power chords, like 2-4, 2-4, or 3-5, etc (6th and 5th strings) many times, and live, I see Broderick holding those same power chords BUT playing ONLY THE 6TH STRING, WHICH IS WHAT I DO NOT GET! arent we supposed to play BOTH the strings?
im definitely confused in rhythm, hope I make sense to sum1.
thanks. 

First thought is that you'd strum/pick the pwr chords however you need to in order to re-create the sound you want. Second thought suggests that were it me wanting to find out what they're doing on a particular track, i'd search net for a tab. If you've already done that, then tube might have the answer under 'Guitar Lessons For Megadeth Songs'...try that maybe. Mind you, i don't use pwr chords much but i understand them.

If you see a player holding a chord but playing less than all of the notes or even one in the case of a two note pwr chord, it's because they only want certain or  only the one note of the pwr chord to ring and also possibly because there is another guitar or a bass player playing the notes/note that they are omitting. I hope this helps zuhairreza !

Cheers,

GuitarZen

just listened to "Tyrant" by Judas Priest off their Sad Wings of Destiny album. Dunno much about them and it seems they are good....
thanks GuitarZen for your reply. I am beginning to understand what you mean. I was thinking more from a limited point of view before, like either its only downpick OR ONLY alt pick,etc etc, and I should follow only ONE method, lol...it seems things are universal...OK, I will take your advice. Thanks.
Thanks for YTube suggestion, I tried searching, but will try again. However, For any Metal fan, I would HIGHLY recommend this website, http://www.obeyyourmattster.com/ < U DONT WANNA MISS THIS GUYS, VIDEO LESSONS, for any1 who did not know of this...
Thanks GuitarZen. Just played Master of Puppets again and it seems my downpicking speed has greatly improved...Cheers! 

Glad i was able to help you zuhairreza ! Reminds me, can you put a vid on tube and if so how 'bout posting one in the members vids section?

Cheers,

GutiarZen

well i have never made a vid of myself lol ...but if anytime i do, i will surely post it at the members vids...
take care, and thanks again!
Cheers,

Zuhair Reza