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From: beres@cadnetix.COM (Tim Beres)
Newsgroups: comp.arch,comp.graphics
Subject: Re: (graphics processor speedups)
Message-ID: <7459@cadnetix.COM>
Date: 17 Apr 89 20:33:37 GMT
References: <28930@apple.Apple.COM> <3300064@m.cs.uiuc.edu> <3880@ficc.uu.net>
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Reply-To: beres@cadnetix.COM (Tim Beres)
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Organization: Cadnetix Corp.,  Boulder, CO
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[Why doesn't DEC use a graphics processor?  Because of CPU speedups?]

Sorry about that paraphrase...Having worked on a number of graphics
accelerators and systems employing the same, I must say that there is 
no way an un-graphics-accelerated system will beat the *performance* of
a CPU-does-the-rendering setup.  Price/performance is another issue - 
definitely not for comp.arch. (-:  The evidence:

	1.  Third-party accelerators having ~5x performance over Sun
	    CPU in pixrect operations [Tech-Source GDS 3800].  

	2.  Sun's GX and GXP series.  These went fairly unnoticed in the
	    recent product announcements, but present evidence of Sun
	    targetting graphics performance.  Even with the new designs
	    giving state-of-someones-art MIPS numbers, they chose to 
	    bring out a spiffy new accelerator.  Having run some benchmarks
	    on the GX, I can safely attest to marked performance gains.
	    I've seen various numbers, but 3-4X over dumb frame buffer is
	    in the ballpark.  With various optimizations, more X's are
	    in order, I'm told.  If I get enough requests and mgmt approves,
	    I'll see if I get can some numbers out to the net.

In my opinion/guess, DEC went unaccelerated due to price reasons.  Likely
wanted the best $$$/CPU MIP ratio at the time.  As someone from DEC pointed
out, it wasn't due to the fact that a raw CPU is faster.  

An interesting side-note:  It appears the future of microcoded graphics engines
are over.  As well, general purpose graphics CPU's *appear* to be numbered.
Gate-arrays to perform specific rendering tasks are the way to go.  This 
statement is doused in gasoline - so flame away.

				Tim

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