Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!purdue!bu-cs!mirror!prism!rob
From: rob@prism.TMC.COM
Newsgroups: comp.sys.ibm.pc
Subject: Re: Ami Bios and the V20
Message-ID: <206900136@prism>
Date: 10 Nov 89 16:32:00 GMT
References: <6129@merlin.usc.edu>
Lines: 16
Nf-ID: #R:merlin.usc.edu:-612900:prism:206900136:000:831
Nf-From: prism.TMC.COM!rob    Nov 10 11:32:00 1989



 > Hmm, I've got a Zenith Z161 (portable - luggable) I just popped my V20
 > in and zingo everything goes. My Norton SI went from 1.0 to 1.8!

  It's been said before, but it's worth repeating - The 1.8 number from
SI is unrealistic (in general, any number from SI comparing different
CPUs is unrealistic). Norton's SI tests speed by looping around an IMUL
and IDIV instruction. The V20 executes these disproportionately quickly
compared to the 8086/88. Since IMUL and IDIV instructions are very rare in
'real world' code, SI's figure isn't meaningful. The same problem comes 
when running SI on 286/386/etc... machines.

   In general, a V20 should give you about a 5 - 10% speedup, possibly
as high as 20 - 30% when running floating point code, which tends to be 
heavy in integer multiplies and divides unless you have an 8087.