From: utzoo!decvax!decwrl!sun!gnu Newsgroups: net.micro.68k Title: 68K vs 286 on floats Article-I.D.: sun.201 Posted: Thu Feb 17 03:47:51 1983 Received: Mon Feb 21 20:16:10 1983 References: ima.286 Anyone who thinks the 286 (80287 co-processor really) is fast on floats has not read the specs. Some timings from published Intel documents: Load 64-bit 10 us Store 64-bit 21 us Add/Sub 14/18 us Mul 32-bit 19 us Mul 80-bit 27 us Div 39 us While the chip can indeed multiply pretty fast, it takes it almost as long to store the result in memory as it does to do the multiply! And to load a value, add another, and store the result takes 45 us -- our 68000 software float is faster than that (tho: it is only operating on 32-bit floats). I can't understand how it can take them 21 us to store 4 words in memory. (Note, these timings are for 5MHz parts. 8MHz parts will be available "later"... I don't know if you can run a 5MHz 80287 with an 8MHz 80286, or even if 8MHz 80286's are available, but of course the 8MHz is what all the slanted comparison ads have been for.) John Gilmore, Sun Microsystems