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From: dripton@netcom.com (David Ripton)
Subject: Re: GPL Observation/Question on CPU cache, Voodoo2 and Thriller 3d frame rates
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Date: Mon, 5 Oct 1998 16:01:47 GMT
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In article <3619d088.13844284@news1.ibm.net>,
Jeff Haas <jlhaas3@ibm.net> wrote:
>On Sat, 3 Oct 1998 20:09:29 -0400, "Mike Petersen"
><mpete@nospam.mnworld.com> wrote:
>
>>You may be able to overclock  a CeleronA to 450, but that doesn't mean it's
>>a p2-450...
>>
>>I have a p2-450 with a Diamond M3D2 (just one), and I get 36fps...
>>
>>Also, remember:
>>If you have an older system, Rendition will probably out perform 3dfx2
>>If you have a P2/???, 3dfx2 will blow away Rendition

>Thanks for the info Mike,  that confirms my thoughts about the lack of
>full cache on the celeronA.  I'm well aware of what I have :) . given
>the cost, it's a great solution until the prices drop.

The Celeron A should be very comparable to the P2 at the same clock
speed -- 128 KB of full-speed cache compares nicely to 512 KB of 
half-speed cache.  Obviously some programs will be faster on one or
the other depending on the core working set, but I really doubt
you'd notice the difference in any game.  (The old L2-cacheless 
Celerons are another story, but even they are good enough for many 
games, since the core working set often fits in L1 cache.)

Increasing your cache size is good, but you get seriously diminishing 
returns in typical programs.  (If your L1 cache has a 90% hit rate,
and L1 plus the first 128 KB of L2 has a 95% hit rate, then all the
additional cache in the world can only come into play 5% of the
time.)

Data point: P2-333 overclocked to 412 MHz.  Voodoo 1 card.  640x480.
32-36 fps when hotlapping at the Glen, with all details on.  Solid
36 fps with a few details turned off.  8 fps in the back of the pits 
behind 19 computer cars, rising to about 25 fps after the start.

Looks like there's a ton of overdraw going on when a lot of cars 
are displayed, and a Voodoo 2's extra fill rate helps a lot in that 
situation.  Given a fast CPU, the game is very playable with a 
Voodoo 1 at 640x480.  (800x600 is noticably slower.)
 
With the Celeron 300a at $143 and Voodoo 1 cards at $49, I don't
think GPL's hardware requirements are out of line.  It would be
nice if the actual requirements were on the box, though.  (The
time spent on the unusable software renderer should have been 
spent on a D3D or OpenGL port, so the people with TNT, i740,
G200, and future 3D cards could play, too.)

-- 
David Ripton    dripton@netcom.com
spamgard(tm): To email me, put "geek" in your Subject line.
