wales@valeria.cs.ucla.edu (Rich Wales) (07/14/88)
I am thinking about buying a 286-based accelerator board for my Taiwanese turbo. My system has an 8-MHz NEC V-20 CPU. The clock speed is software- switchable to either 4.77 or 8 MHz. The RAM chips are 150-nsec. The accelerator I am currently thinking of is the "Orchid Tiny Turbo 286" -- a half-sized card unit with room to add an 80287 coprocessor. One feature of this board which appeals to me is that it has a socket for your original CPU chip -- and a little toggle switch accessible from the back of the computer which lets you select either the 286 or your original CPU. The Orchid also claims to be usable at either 5 (I assume they really mean 4.77) or 8 MHz. Does anyone out there who is using (or has tried) the Orchid Tiny Turbo 286 know whether it can in fact be used in an 8-MHz turbo XT? Would I be able to drive it at the 8 MHz clock speed? Even at the standard 4.77 MHz speed, how much faster is it going to be than my current NEC V-20 system at 8 MHz? Would I have to replace my 150-nsec RAM chips with 120's (or faster?) in order for an accelerator to be worth the expense? Is this particular accelerator board a good one? I am very open to suggestions of better (faster and/or more reliable) units. The Orchid is currently selling for $290 at Egghead -- though I assume I can find a lower price if I shop around a bit. -- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683 3531 Boelter Hall // Los Angeles, California 90024-1596 // USA wales@CS.UCLA.EDU ...!(uunet,ucbvax,rutgers)!cs.ucla.edu!wales "We would all become unpeople, undoing unthings untogether."
adam@gpu.utcs.toronto.edu (Adam R. Iles) (07/15/88)
In article <14382@shemp.CS.UCLA.EDU> wales@CS.UCLA.EDU (Rich Wales) writes: >My system has an 8-MHz NEC V-20 CPU. The clock speed is software- >switchable to either 4.77 or 8 MHz. The RAM chips are 150-nsec. >The accelerator I am currently thinking of is the "Orchid Tiny Turbo >286" -- a half-sized card unit with room to add an 80287 coprocessor. A week ago I purchased just such a card for a similar setup (except I'm using a 8088-2 and it's not software switchable.) The documentation, however, SUGGESTS that you DON'T use it with a turbo system or a 8088-2, V-20 or several other replacement chips. This card comes with an 80286 and an 8K cache on an 16 bit bus (to the 80286.) >the back of the computer which lets you select either the 286 or your >original CPU. The Orchid also claims to be usable at either 5 (I assume >they really mean 4.77) or 8 MHz. This is reffering to the 80287 not the 8088 or equivilent :-( which leaves you with only the 4.77 Mhz bus. >Does anyone out there who is using (or has tried) the Orchid Tiny Turbo >286 know whether it can in fact be used in an 8-MHz turbo XT? Would I >be able to drive it at the 8 MHz clock speed? Even at the standard 4.77 >MHz speed, how much faster is it going to be than my current NEC V-20 >system at 8 MHz? Would I have to replace my 150-nsec RAM chips with >120's (or faster?) in order for an accelerator to be worth the expense? I haven't had much time to test the board thuroughly, but it seems to run fine at 4.77 MHz, but it won't run at 8 Mhz at all. Since I don't have a V-20 in my machine I can't compare it to the V-20, but it seems to run some programs at upto 4X as fast as the 8088-2 (at 4.77 Mhz.) One thing to remember is that the Tiny Turbo is still going through the 4.77 Mhz 8-bit bus so disk accesses and memory fetches outside the cache will be as slow as a regualar PC. If you run programs that execute a lot of tight loops and aren't I/O intensive it should do a good job at improving their performance, though. >-- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683 > 3531 Boelter Hall // Los Angeles, California 90024-1596 // USA > wales@CS.UCLA.EDU ...!(uunet,ucbvax,rutgers)!cs.ucla.edu!wales > "We would all become unpeople, undoing unthings untogether." Adam Iles -- adam@utgpu -- adam@vm1.utcs.utoronto.ca All comments above do not necessarily reflect the beliefs or opinions of any person alive or otherwise. -- Any opinions stated above may, or may not, refect those of any sane person living, dead, or just sleeping. Adam R. Iles: adam@utgpu
wales@valeria.cs.ucla.edu (Rich Wales) (07/16/88)
In article <14382@shemp.CS.UCLA.EDU> I wrote the following:
I am thinking about buying a 286-based accelerator
board for my Taiwanese turbo.
My system has an 8-MHz NEC V-20 CPU. The clock speed
is software-switchable to either 4.77 or 8 MHz. The
RAM chips are 150-nsec.
The accelerator I am currently thinking of is the
"Orchid Tiny Turbo 286" -- a half-sized card unit with
room to add an 80287 coprocessor.
I just got off the phone with a technical support person from Orchid.
She says -- very emphatically -- that the Orchid Tiny Turbo 286 *ABSO-
LUTELY WILL NOT WORK AT ALL* on a dual-speed NEC V-20 system. It
*MUST*, she says, be an 8088-based system running at 4.77 MHz *ONLY*.
I was unable to get any intelligible explanation as to just why the
Orchid Tiny Turbo 286 wouldn't work in my system. I asked, what if I
kept the clock speed at 4.77 MHz all the time -- and the Orchid person
said that wouldn't matter, their card still wouldn't work for me.
She said that Orchid has another product -- the Twin Turbo 12 -- that
does work OK in a dual-speed V-20 system.
I also talked with a technical support person from AST Research, about
their Hot Shot/286 accelerator card. Same story -- AST says their Hot
Shot/286 *WILL NOT WORK* on a V-20 system; *ONLY* on an 8088 system.
And again, no intelligible reason given; just that it won't work.
I suppose my only feasible upgrade route may turn out to be to get an
AT clone motherboard (something I'm not sure I'm prepared to do right
now; and please don't flood me with "why not?"s). But let me ask again:
Has anyone out there had any first-hand experience with 286-based
accelerator boards for PC/XT systems?
Can anyone offer a sensible explanation as to why an accelerator board
built for the 8088 would not work on a dual-speed NEC V-20 system --
even assuming that the clock was *always* run at 4.77 MHz whenever the
accelerator board was being used?
-- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683
3531 Boelter Hall // Los Angeles, California 90024-1596 // USA
wales@CS.UCLA.EDU ...!(uunet,ucbvax,rutgers)!cs.ucla.edu!wales
"We would all become unpeople, undoing unthings untogether."