[mythtv-users] Trouble with HD playback

[Anthony Vito]

> > More to the point, clock multipliers aren't always adjustable (varies from
> > mobo to mobo, chip to chip), so a chip designed to run on a 400MHz bus with a
> > 5.5x multiplier would run a good amount slower. If you can adjust the
> > multiplier and the price is the same, I'd get the 400 variant, just in case I
> > ever upgraded to a board w/a 400MHz FSB.
> 
> I must confess a little ignorance here.  Given a motherboard that can
> only support a 333MHz FSB:
> 
> Are you saying that if I purchase an Athlon XP 3000+ rated for a 400MHz
> FSB, it might actually run slower than if I purchase an Athlon XP rated
> for a 333MHz FSB?  If so, should I be looking at a lower-end Athlon XP?

Yes, but he's didn't get the details.... the FSB is DDR, multiplied at
the actual clock timing, not the DDR timing. So a 400 Mhz FSB Athlon
XP 3200 ( 2.2Ghz ) has a 11x multiplier ( 200 X 11 ) therefore,
without unlocking the chip or otherwise being able to change the
multipler, that same chip running at 333 Mhz FSB would run at ~1833
(166 X 11).... If you have a board that supports changing the
multipler, and changing the core voltage, get a Mobile XP 2800 and run
it at  11x 200, It will throw off less heat, and probably only need
1.55 or so volts to pull it off...... FSB absolutely makes a HUGE
difference with Athlons. P4's REQUIRE a really fast memory subsystem
to get even good performance, this is where the misleading information
comes from. Athlons will benefit nearly as much percentage wise from
increased memory performance... they just don't crap out when they
have less then an 800Mhz bus ;)

I really need to get some time and write up my experiences with
building an HDTV front end. I believe it would help a lot of people.


-- 
Anthony Vito
anthony.vito at gmail.com

Biostar M7NCG 400
Mobile XP 2800 @ 2.2Ghz ( 12x183 )
512M DDR Mushkin
pcHDTV 2000
Using Onboard GFMX for Xv
Infocus X1 (800x600 @ 100")