Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!knuth!mjbtn!raider!elgamy!elg From: elg@elgamy.RAIDERNET.COM (Eric Lee Green) Newsgroups: comp.sys.amiga.advocacy Subject: Re: Blitter vs. 040 (was: Computer Architecture question Message-ID: <00674001103@elgamy.RAIDERNET.COM> Date: 11 May 91 22:31:43 GMT References: <3310.tnews@templar.actrix.gen.nz> Organization: Eric's Amiga 2000 @ Home Lines: 32 From article , by melling@cs.psu.edu (Michael D Mellinger): > In article <3496.tnews@templar.actrix.gen.nz> jbickers@templar.actrix.gen.nz (John Bickers) writes: > Hmmm. So, how well can the NeXT perform animation? The 68040 is > definitely faster than 2 68030s. In an 040 A3000 does the blitter > become a bottleneck. Meaning could things be done faster if the CPU > was used instead? The blitter must offer some functionality that a > "normal" CPU doesn't. Just out of curiousity, where is a color card located in the NeXT? On a 10mhz I/O expansion bus? That's the primary failing of most computers... they don't have a fast I/O bus. E.g. these "fast" '386 machines are most often cramming bytes into their super-hi-res VGA cards 16 bits at a time over a 8mhz (or 10mhz) bus... with bank switching, no less, to deal with the fact that you can't fit that much memory into a MS-DOS memory space. What a performance nightmare. From what I understand, the Mac folks have a similar problem with their NuBUS implementation... i.e., the processor can't jam bytes into the framebuffer at anywhere near the processor's top speed. For that matter, neither can the Amiga, in its current incarnations... but the A3000 still has twice the bandwidth into video memory, compared to the typical '386-based PC. The blitter's functionality mostly applies to multitasking environments when you're talking 68040's. Even a 68040 isn't an unlimited resource. Note that there exists software patches for the A3000 to patch the OS's BlitBitMap etc. calls to use the CPU instead of the blitter... but most people still don't do it, because other processes slow down drastically when so much CPU is being used to shove bytes around on the screen. (Even though it DOES speed up the screen scrolling and such). n -- Eric Lee Green (318) 984-1820 P.O. Box 92191 Lafayette, LA 70509 elg@elgamy.RAIDERNET.COM uunet!mjbtn!raider!elgamy!elg