ndeng@EULER.BERKELEY.EDU (11/29/89)
The latest issue of PC-Magazine (vol.8, no.21) reported a new 80387 compatible math-coprocessor, FasMath 83D87 from Cyrix Co. According to the company, this chip can be up to 10 TIMES FASTER than 80387, and is fully pin and SW compatible. I am extremely interested in this, but thought it's almost incredible. If this is proven, then 80387 and Weitek are all dead, and many accelerator boards become obsolete. Does any number-crunching guru has hand-on experience about this chip? Could any of you share you experience/excitement with netters? ndeng@euler.berkeley.edu
afg@cbnewsl.ATT.COM (andrew.goldberg) (11/29/89)
In article <8911290805.AA05793@euler.Berkeley.EDU>, ndeng@EULER.BERKELEY.EDU writes: > > The latest issue of PC-Magazine (vol.8, no.21) reported a new 80387 compatible > math-coprocessor, FasMath 83D87 from Cyrix Co. According to the company, this > chip can be up to 10 TIMES FASTER than 80387, and is fully pin and SW compatible. I am extremely interested in this, but thought it's almost incredible. If this > is proven, then 80387 and Weitek are all dead, and many accelerator boards > become obsolete. Does any number-crunching guru has hand-on experience about > this chip? Could any of you share you experience/excitement with netters? > Well, hold on to your 387. It's not dead yet. Pc Week showed the results of some testing (November 6, 1989, p. s/26) that showed that the only significant improvements in the Cyrix chip are in the transcendental functions. And they only found about a factor of two, not ten. Andy Goldberg AT&T Bell Laboratories Parsippany, New Jersey afg@vilya.att.com
chasm@attctc.Dallas.TX.US (Charles Marslett) (11/29/89)
In article <8911290805.AA05793@euler.Berkeley.EDU>, ndeng@EULER.BERKELEY.EDU writes: > The latest issue of PC-Magazine (vol.8, no.21) reported a new 80387 compatible > math-coprocessor, FasMath 83D87 from Cyrix Co. According to the company, this > chip can be up to 10 TIMES FASTER than 80387, and is fully pin and SW compatible. > I am extremely interested in this, but thought it's almost incredible. If this > is proven, then 80387 and Weitek are all dead, and many accelerator boards > become obsolete. Does any number-crunching guru has hand-on experience about > this chip? Could any of you share you experience/excitement with netters? > > ndeng@euler.berkeley.edu I have played a bit with it: it is definitly faster than the intel 387. It also runs a lot cooler (they claim some despicably low power consumption, and I do believe that!). As I understand it, it often runs ten times as fast internally that does the intel part, but after you add in the overhead (bus cycles from memory to 386 to FPU to 386 to memory, etc.) the ratio is a lot more like 2:1 or 3:1. Cyrix seems to have done a bit more to exactly match the numbers intel generates in their transcendental functions (good, bad, random, or whatever) that IIT has, but the tests I have run show differences between the three vendors to really be down in the mud (about 1 in 10 evaluations report differences, and usually the difference is because the actual value is almost exactly halfway between the two reported values!). Recap: FasMath is faster and much lower power, IIT's 3c87 is faster (about the same power requirements?), and Intel's 387 is more available (and maybe cheaper). Charles Marslett STB Systems, Inc. <-- apply all standard disclaimers [I wrote the SSDC/IIT demo/benchmark program, also.]
davidsen@sungod.crd.ge.com (William Davidsen) (12/04/89)
The speed increase over the 387 is not across the board, for Cyrix or
ITT. The chip which may be useful is ITT's replacement for the 287. Most
of the 386s made in 86 and 87 have only a 287 socket (Intel didn't even
have the sockey specs available). This includes all the early AMI and
Compaq systems (like mine). Replacing the 10MHz 287 with a 20MHz ITT
version would give a big kick just from clock speed. I have not seen a
benchmark on the ITT chip, but I suspect that the improvement is mostly
in transcendental functions.
bill davidsen (davidsen@crdos1.crd.GE.COM)
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"Stupidity, like virtue, is its own reward" -me