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xt cpu upgrade 8088 to necv20

G

genocho

Experienced Member
Joined
Jan 14, 2008
Messages
63
Hi,

I recently upgrade my old pc xt with 8088 cpu to a necv20 cpu.

A friend of my tell to me that this kind of upgrade makes my old pc more faster, and really is, with landmark cpu test pass from 5,08 mhz to 5,98 mhz (6mhz at for landmark test), the real speed is 9,54mhz.

Now this ganance of speed is testimonial but in the ninetys was really awesome and expensive of course.

I tried several programs and games and really show that is a little faster, but I have a problem.

For any reason that can´t know, the parallel port not run. If plug mi zip drive, the pc makes 3 beeps and dont boot.......

Perhaps the internal address of the necv20 cpu 16 bits, is different from the 8088 (8 bits) and makes any conflict with the hardware.............

Is really a shame, because the necv20 is better than the 8088.

If any know any reason or any jumper exists for change the parallel port address, I will thank a lot.

An isa parallel port dont help me, because this pc only have 1 isa slot and now is used by the vga card.

Well, any idea, or help is accepted,

Best Regards,

Me
 
genocho said:
Perhaps the internal address of the necv20 cpu 16 bits, is different from the 8088 (8 bits) and makes any conflict with the hardware.............
Click to expand...

Not quite sure what you mean here, but I'll give it a shot...

Both the i8088 and the NEC V20 have 8 data bits & 16 address bits, so are completely compatible in that regard. The 16-bit version from NEC is the V30, which is compatible with the i8086.

Not all motherboards can use the V20, but I gotta admit, this is the first one I've personally heard of that chokes on it.

--T
 
Terry Yager said:
Not all motherboards can use the V20, but I gotta admit, this is the first one I've personally heard of that chokes on it.
Click to expand...

Might not be the same issue, but when I played with an NEC V20 on a non-IBM compatible machine, I did have one or two problems. The one I remember was to do with software timing loops within the diskette format program. The slightly faster processor completed the timing loops too quickly between writing pulses or whatever it was to the diskette. Could be a similar timing issue with the parallel port.

Steve
 
fully loaded

fully loaded

genocho said...because this pc only have 1 isa slot
Click to expand...
A few questions:
What else do you have in the box ? (It's a real XT, right, not a clone ?)
Does it start to beep after it tries to boot from the drive, or during POST ?

Here's a link to beep codes for an XT.
http://www.postcodemaster.com/b_ibmxt.shtml
From your description, the beeps sound like a video problem, hence the questions about installed hardware & if it's a clone or not.
patscc
 
My Kapro XT came with a NEC V20 8Mhz installed, no idea if it is a speed demon since I never benchmarked it. I think the machine shipped with the V20 so it is not an aftermarket mod.
 
Kaypro XT

Kaypro XT

Terry Yager said...I haven't run across the XT model before
Click to expand...
Neither have I. I keep running across references, though, but not enough to tell if it actually existed, existed only in Europe, was a prototype, or what. About all I know is that it has a V20. Any Kaypro experts out there know ?
patscc
 
patscc said:
Neither have I. I keep running across references, though, but not enough to tell if it actually existed, existed only in Europe, was a prototype, or what. About all I know is that it has a V20. Any Kaypro experts out there know ?
patscc
Click to expand...

Y'know, I wasn't certain that the K-II with vertically-mounted drives actually existed in the wild either, till Tez dug one up. Anything can happen...

--T
 
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