rch@vaxine.UUCP (Bob Hartman) (09/06/85)
To those of you that saw my posting last week about the new NEC V20
and V30 chips, thanks for responding and telling me where to get one. I got
mine through JDR Microdevices ($20.95 - advertised in BYTE).
As you may or may not know, the V20/V30 chips are 8088/86 look-alikes
that are sold by NEC. The differences are many, but mainly in that the V20/30
are SUPERSETS of the 8088/86 family. For example, they support 8080 emulation,
contain the 80186 instruction set, plus a bunch of new instructions. The real
kicker is that the V20 is faster than the 8088 in most instructions, and the
rest of the instructions are at the same speed. Big gains are in relative
addressing modes where the V20 takes 2 clock cycles for the address compared
to the 8088's 5-12 cycles. Anyway, the moral of the story is that you can
buy this chip, stick it into your PC in place of the 8088, put the cover back
on, and everything will work as before. The only difference is that you will
get a 5-100% improvement in performance depending upon the software being used!
I found that in general I was getting about 25% improvement. For $20.95, you
can't beat this system upgrade. I checked out every program I own (I run the
UN*X Gateway BBS - Fido 101/101, and I have about 20MB of programs), and they
all ran perfectly (and yes, that includes with and without an 8087 chip). The
funny thing is that unlike the AT, programs that use the timer interrupt do not
run faster. This is because the clock frequency is the same, just the
instructions execute faster.
Hope this helps people who were wondering.
- Bob Hartman -
UUCP: {decvax,ihnp4}!encore!vaxine!rch
BBS: Fido 101/101 - (603) 888-5433 300/1200/2400 baudkim@mips.UUCP (Kim DeVaughn) (09/10/85)
[ ... go ahead, eat my bits ... ] > > To those of you that saw my posting last week about the new NEC V20 > and V30 chips, thanks for responding and telling me where to get one. I got > mine through JDR Microdevices ($20.95 - advertised in BYTE). Does anyone on the net know where I can get a NEC V30 (the 8086 compatible chip)? I called JDR Microdevices, and was told they only carry the V20. I need an 8 MHz chip for my Fujitsu Micro-16s. Please send me e-mail, and I'll summarize to the net. Thanx alot, /kim -- UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!kim DDD: 415-960-1200 USPS: MIPS Computer Systems Inc, 1330 Charleston Rd, Mt View, CA 94043
bc@cyb-eng.UUCP (Bill Crews) (09/11/85)
> The funny thing is that unlike the AT, programs that use the timer interrupt > do not run faster. This is because the clock frequency is the same, just the > instructions execute faster. > - Bob Hartman - There are often many clocks in a computer system. Let's not confuse cpu clock frequency with the interval between timer ticks. The timer interrupts 18.2 timers per second, just like the PC. -- / \ Bill Crews ( bc ) Cyb Systems, Inc \__/ Austin, Texas [ gatech | ihnp4 | nbires | seismo | ucbvax ] ! ut-sally ! cyb-eng ! bc
wdm@ecn-pc.UUCP (William D Michael) (09/13/85)
In article <640@vaxine.UUCP> rch@vaxine.UUCP (Bob Hartman) writes: > > To those of you that saw my posting last week about the new NEC V20 >and V30 chips, thanks for responding and telling me where to get one. I got >mine through JDR Microdevices ($20.95 - advertised in BYTE). > --- a discussion of the chips followed --- Does anyone know if NEC plans an 8087 upgrade? Also, has anyone tried the v-20 and -30 with an 8087? How does it work? It seems to easy to unplug the '88 plug in a v-20 and get a 30% increase in speed. bill "my faith in american semiconductor manufacturers is slipping" michael (wdm@pur-ee)