How do I maximize performance of an IBM PC/XT?

Hello and greetings,
I am looking for someone who knows more about the old IBM PCs and someone who would know how to maximize the performance of an IBM PC/XT using 3rd party upgrade CPU solutions, 8 bit compatible ISA VGA cards, etc. I am looking into getting the PC/XT for use as a MS-DOS machine, and upgrades would be nice. It would also be nice if someone could tell me what was the highest capacity hard drive that the motherboard would register. If someone lists some things, could you state the possible specs of a machine with those cards and upgrades.
-ET

What are you trying to achieve with such old hardware?

maximize performance

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Utilize a more modern platform

Exactly. No reason not to get a 486DX66 or something along those lines.

XT/AT REALLY REALLY REALLY sucks. REALLY.

mistersprinkles said:

XT/AT REALLY REALLY REALLY sucks. REALLY.

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I feared that this was true, but is there an upgrade path, maybe going as far as swapping the motherboard with one out of a compatible PC/XT clone with better specs like a 286 or even a 386, hoping that the ports match up with the space on the back, and use it like that? I'm hoping that I get something at least better than the PC/AT.

Not really man

mistersprinkles said:

Not really man

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Thanks for encouraging me to wake up and smell the coffee. I'll just see if I can get a 5x86 build in the case of a PC/XT or a 5150.

Why would you gut a 5150? They are collectors items.

I don't think you ever really addressed the 'why are you dicking around with this shenanigans'

What is the goal you have in mind for this machine as far as the usage scenario? If you are looking to play old games you would be better served by a fast 486

Problem is once you start changing the innards then the only bit of an IBM PC/XT that you have left is the tin box it came in.

_Pete_ said:

Problem is once you start changing the innards then the only bit of an IBM PC/XT that you have left is the tin box it came in.

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And...? I was going to get a PC or PC/XT look alike or clone, gut it, and put a 5x86 or P1MMX motherboard or setup in there. I liked the aesthetic of a PC or PC/XT. The only challenge that would face me is that how would I get a modern-ish CRT to look like a 5151 or 5154, as those are collectors items.

That's when I started getting into building computers, 1994/95 time frame. Use to have boxes and drawers full of the stuff. Got rid of most of it a few years ago. Honestly I hated those cases

I started my computing "life" with an IBM PC in 1984 and know quite a bit about the PC & XT. As others have stated, a newer 486 based computer would be faster but there are still some things you can do to boost performance on an XT. It's a fun exercise to see what kind of performance you can get out of the old hardware but newer cpus still blow it away.

First thing is memory, bump up the regular memory to 640K. Also add a memory card with either extended or expanded memory on it and use that extra memory for a RAM disk. A RAM disk is much faster than the mechanical drives that the PC & XT class machines used. The downside to a RAM disk is that the files you put on there don't survive a reboot so they need to be recopied to the RAM drive whenever you boot but, once copied, the read/write performance is greatly enhanced.

The XT used the Intel 8088 CPU. If you can locate one, an NEC V20 cpu https://en.wikipedia.org/wiki/NEC_V20 can be dropped in. The V20 uses the same instruction set as the 8088 but is on the order of 15-20% more efficient so will give a slight performance increase to the machine. You could also experiment with overclocking. If you go away from IBM brand XT boards, there were manufacturer's that made clone XT boards that ran as fast as 10-12Mhz whereas the IBM XT clocked the 8088 at 4.77Mhz.

Also, you could replace the hard drive with a CF (Compact Flash) card reader that will give you faster and larger capacity storage. https://www.lo-tech.co.uk/wiki/XT-CF-lite_rev.2

My first build in 1985 was a clone of an IBM XT. Mine had a V20 running at 8Mhz vs the IBM with a 8088 running at 4.77Mhz, 640K main memory plus 2 MB of Expanded memory. I ran a 30MB hard drive as opposed to the 10MB drive the IBM came with. My build cost me less than 1/2 of what it would have cost to buy the IBM XT and had easily twice the performance.

strollin said:

My first build in 1985 was a clone of an IBM XT. Mine had a V20 running at 8Mhz vs the IBM with a 8088 running at 4.77Mhz, 640K main memory plus 2 MB of Expanded memory. I ran a 30MB hard drive as opposed to the 10MB drive the IBM came with. My build cost me less than 1/2 of what it would have cost to buy the IBM XT and had easily twice the performance.

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You built an XT clone? That's hardcore bro.



^You must change your avatar to this now

eli573 said:

The only challenge that would face me is that how would I get a modern-ish CRT to look like a 5151 or 5154, as those are collectors items.

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Why not use a 4:3/5:4 panel and build a crt cabinet around it?

Cromewell said:

Why not use a 4:3/5:4 panel and build a crt cabinet around it?

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I guess I could try to, but I've never made a look alike monitor. Sounds fun!

How about don't do this, period. Have you ever used an XT? Faster than a speeding amoeba it is. Almost as fast as a speeding snail.