Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!bagate!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.hardware Subject: Re: Slow GVP '030 accelerator board Message-ID: <15970@cbmvax.commodore.com> Date: 20 Nov 90 06:34:19 GMT References: <1990Nov16.175346.4884@maverick.ksu.ksu.edu> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Distribution: usa Organization: Commodore, West Chester, PA Lines: 43 In article <1990Nov16.175346.4884@maverick.ksu.ksu.edu> yeewei@matt.ksu.ksu.edu (Yee-Wei Huang) writes: > I recently purchased a GVP 28mhz '030 accelerator board, and >it is not performing up to par. >GVP 3001 accel card w/o '882 and w/o 32 bit ram ^^^^^^^^^^^^^^-------- Great Ceasar's Ghost, Superman! > When I run performance tests on the machine, I show only a 20% >increase over the stock 68000! That's just about what you should expect to see, without any 32 bit RAM. Without faster and wider memory, the clock speed is going to make very little difference, the CPU will be memory bound. And, with 16 bit memory, the 68030 is less efficient than the 68000. 680x0 instructions are based on 16 bit words, yet the 68030's prefetch mechanism always grabs 32 bits at a time for any instruction fetch, even if the second 16 bits won't be used. So, on a 68030 with 16 bit RAM, a certain % of the memory cycles you run do absolutely nothing relative to a 68000. You do get performance increases as well, thanks to full 32 bit ALUs and better microcode, but you still don't win in many cases until the caches are enabled. If you're running with the GVP standard Startup-Sequence, you will have the data cache turned on too, which should help you out a bit (the OS turns on the instruction cache). If not, copy SetCPU over from the GVP disk and run "SetCPU CACHE" somewhere in your Startup-Sequence. >Another funny thing: all my system performance and monitering >software tells me that I have an '020 instead of an '030. Under 1.3, the OS doesn't differentiate. If you run SetCPU first, and you have software that follows the OS 2.xx conventions for CPU identification, you'll find that a 68030 will be reported. Really, the only real use for a 68030 without 32 bit RAM would be in floating point operations, which of course require an FPU. A plain '030 with no FPU and no 32 bit RAM is about the most expensive way I can think of to improve your system performance by around 20%. Add some decent 32 bit memory and you'll see more like 400%-800% improvement. That's why the A2630 doesn't come without 32 bit RAM. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Standing on the shoulders of giants leaves me cold -REM