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From: melling@cs.psu.edu (Michael D Mellinger)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Blitter vs. 040 (was: Computer Architecture question
Message-ID: <6o6Hk!=@cs.psu.edu>
Date: 11 May 91 00:23:11 GMT
References: <1991May9.070349.15151@neon.Stanford.EDU>
	<3496.tnews@templar.actrix.gen.nz> <vbcH!4p@cs.psu.edu>
	<1991May10.180908.29565@convex.com>
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In-Reply-To: swarren@convex.com's message of 10 May 91 18:09:08 GMT
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In article <1991May10.180908.29565@convex.com> swarren@convex.com (Steve Warren) writes:

   In the A3000, the 68030 can update display memory faster than the blitter can.
   This does not mean that there is no advantage to using the blitter (and the
   blitter does not loose by *that* much).  The fact is, if the blitter is used
   to manage the display and the '030 is able to stay out of display memory, then
   the '030 will be able to "multiprocess" in parallel with the blitter.  So if
   you have calculations that need to be performed then, it is advantageous to use
   the blitter to offload graphic manipulations from the CPU.

   What is the avg. available bandwidth from the NeXT '040 directly into display
   memory?  The performance of the CPU chip is not as important as the
   availability of the display memory bus to the CPU.

The 040 is equal to at least 3 68030's.  One would think that decent
animation could be done on the NeXT.  It might just be a matter of
being able to interrupt the OS on a regular enough basis to get smooth
animation, which might be a problem at the current time because the
Mach kernal cannnot be interrupted.

Does anyone know the bandwidth from the NeXT 040 to memory?

-Mike