CompuServe Messages

040 Accelerator

    02-Jul-91 04:10:00
Sb: #26833-040 Accelerator
Fm: daniel wolf 70250,626
To: BArry Cooper 75746,3500
some software may be able to run MUCH faster, but I have seen too many incorrect claims for 040 floating point performance and overall performance. I'll bet that an 040 at 25mhz isn't too much faster than an 030 at 50mhz unless code is specially optimized for the 040. While some claim huge floating point speed gains for 040 (specifically the misleading Amiga World article recently), note that the built-in floating point on the 040 is only simple arithmetic – sines, cosines, etc. must be emulated in software. The 040 does NOT have a complete 881/882 type capability built in, only add/subtract/multiply/divide (maybe square root, too?). those four functions should be REAL fast, though, even much faster than they would be on an 881/882. My guess is that real world benchmarks will tell. I tried FractalPro on Progressive Peripherals' prototype 040 board at AmiExpo October 1990 and it was about 20-30% faster than a 25mhz 030 (using a 25mhz 040 prototype chip). FractalPro is ALL integer code – no floating point. That should tell you something – claims for 20Mips IMPLY that the 040 should run about 10X faster than a 25mhz 030 – but, plain and simple, IT DOESN'T. I may be able to re-code FractalPro's math to optimize its performance on 040 when it becomes truly available at reasonable cost as it has larger caches, but I've already paid a great deal of attention to 020/030 optimization (not to mention optimization of the separate routines in FractalPro for those machines which have 68000/010). I'm not sure how much extra speed I'll squeeze out of the 040 with code which is already pretty optimized on 020/030. FractalPro is a good benchmark, though, nearly and acid test of integer performance. I want one, too, though! To paraphrase Vince Lombardi, Speed isn't everything … it's the ONLY thing.