Let's see, in 1984, Compaq released the first Compaq DeskPro personal
computer, which was faster than the IBM XT. There were several reasons,
that went far beyond the fact that the CPU was the 9.54MHz Intel 8086
processor instead of the 4.77MHz Intel 8088 processor in the IBM XT system.
THe DeskPro had a better motherboard in several respects, even though it
still had all 8-bit slots of the XT. They continued to use the exact same
form-factor case for the DeskPro 286/12, which had two 8-bit slots and 6
16-bit slots, and an 12.5MHz Intel 80286 CPU. My DeskPro 386/25 Model 300
of November, 1988 BIOS date vintage used the same case as the original
DeskPro. The DeskPro 386, the original 16-MHz 80386-based machine used the
same case form factor as the DeskPro 286/8 with the 7.16MHz 80286. The
DeskPro 386/20 used the same case as the 386/25. The DeskPro 386/33 and
386/33 EISA used a different case. There were numerous other 80286 and
80386-based Compaq DeskPro machines of different designs and with letter
designators such as DeskPro S, M, N, E, among others.
In the early 80286 days, IBM actually made an XT 286 machine, with all 8-bit
slots, the XT case, and a 7.16MHz 80286 processor. I actually saw one of
those beasts about three years ago, still working happily in somebody's home
chugging along with DOS and WeirdPerfect 5.0.
I've seen people successfully putting 80386 and 80486 motherboards into true
IBM XT cases. My buddy who enjoyed doing that just because he could, first
put a "Baby AT" board in an XT case. Since it ran an Intel 20MHz 386SX
processor, he called it his "386SXT". The last I heard, the motherboard
living in that case was an 80486 board with an AMD 80486DX2/80, running at a
50MHz bus speed, making it a "DX2/100" system, and it was running Windows
95. The proud legend on the front of the case still proclaims IBM PC XT!
Several suppliers made 200-watt XT case power supplies, so power was not a
problem. Anyway, think about how much startup power you needed to spin up
one of those hulking 5MB full-height 5.25-inch form factor SeaGate ST-506
MFM hard drives, along with one of those hideous hulking 5.25-inch floppy
drives, and one of those nasty CGA cards with as many as 86 different chips
on it, not to mention all those 256K-by-1 bit and 64K-by-1-bit DRAM chips,
and you wonder how they even thought a 63- or 65-watt power supply would be
enough anyway! Actually, they quickly went to a 150-watt power supply. You
could still flicker your overhead lights and drive your TV picture bonkers
for a couple of seconds when you started up one of those beasts! I saw more
than one 80286-based PC that couldn't hold a candle for real-world,
get-the-job-done speed performance with that 9.54MHZ 8086-based Compaq
DeskPro that I had, especially after I replaced the 9.54MHz 8086 CPU with
the NEC V30 processor.
Reply to: [EMAIL PROTECTED]
Brent Reynolds, Atlanta, GA USA
All computers wait at the same speed,
Unless you got a bad Delay command.
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