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From: erik@westworld.esd.sgi.com (Erik Fortune)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Mentor & Trident VGA cards - which one is the best ?
Message-ID: <1991Apr12.110818.7937@odin.corp.sgi.com>
Date: 12 Apr 91 11:08:18 GMT
References: <1991Apr3.071713.6290@fel.tno.nl> <3725@d75.UUCP> <1991Apr11.095521.26017@Informatik.TU-Muenchen.DE>
Sender: news@odin.corp.sgi.com (Net News)
Reply-To: erik@westworld.esd.sgi.com (Erik Fortune)
Organization: Silicon Graphics Inc.
Lines: 38

In article <1991Apr11.095521.26017@Informatik.TU-Muenchen.DE>,
roell@informatik.tu-muenchen.de (Thomas Roell) writes:
>     (lots of good analysis of vga speed omitted)
>	74	VGA read/write
>	 4      movsl for buffering
>	 5      storing the buffered data into memory
>	 4	movsl for bltting from memroy into VGAs.
>	 0      reading data from cache
>        --
>        87      cycles
>
>This means that the TVGA8900 is at least 12% slower. At an average I assume
>about 20% slower performance than the ET4000 is they have the same memory
>troughput.

Of course, the number you *really* want to reduce is that VGA read/write 
number. Using VRAM or clever VGA design (like the high(er)-speed cache on 
the video-7 fastwrite) should be able lower that number substantially.   
Of course, the cleverly designed VGAs aren't going to sell for US$130 
any time soon.

>But if you really need speed, forget about VGA. Buy a 8514. Benchmarks:
>
>	VGA 640x480x256          6600 xstones	ET4000
>        VGA 1024x768x256         4800 xstones
>       8514 1024x768x256	26300 xstones	WD9510

The 8514 is nice, but if you really need speed, forget about the PC:-).  
I'm from the workstation world, and most PC-based servers I've seen 
are slow compared to even the typical workstation.   The machine on
my desk can do solid fills at something like 140 million pixels per
second.

Of course the machines I'm talking about have many times the horsepower
and bus bandwidth of the PC, but who ever said we had to make fair
comparisons:-).

-- Erik