Path: utzoo!attcan!uunet!super!udel!mmdf From: iphwk%MTSUNIX1.BITNET@cunyvm.cuny.edu (Bill Kinnersley) Newsgroups: comp.sys.amiga Subject: Re: CMI 68000 2x Message-ID: <4253@louie.udel.EDU> Date: 27 Sep 88 01:03:31 GMT Sender: mmdf@udel.EDU Lines: 32 [In "Re: CMI 68000 2x", Davis said:] : In article, mp1u+@andrew.cmu.edu (Michael : Portuesi) writes: : > Could you post some benchmarks to validate this claim? The CMI board : > sounds interesting, but I wouldn't consider buying it without having : > heard hard facts : Yes, I too am in favor of benchmarks, if they are good I would seriously : consider buying this product. So please post them to the net. : : | Mike Davis : | ..!att!ihlpm!jmdavis : I have a board which is somewhat similar, an 8MHz 68010/68881 combination from Netch Comp Prods. I would like to benchmark it too...could someone suggest a *good* test to run? (e.g. not Savage!) Here are some qualitative impressions of the board I have: 1) Impressive claims for speedup are hard to verify in practice. True, you can do things like square roots and cosines much faster with the 68881. But even programs which appear to be very numerically intensive wind up being dominated by the speed of the simplest operations: adds, subtracts, moves, stores, etc. 2) Both the 68000 and 68010 drive the 68881 as a peripheral device. This plus the need for decoding the floating point instructions in software make things much slower than a 68020/68881 would be. 3) My experience is that I can expect to do IEEE with the board about as fast as FFP without the board. Of course the 68881 will only do IEEE. The net result is that I get double precision for free. So if my programs needed that much precision I would be better off. They usually don't.