View Full Version : Cyrix Cx486DRx2 80386 to 80486 Upgrade CPU on eBay

IBM Portable PC
April 13th, 2016, 05:53 PM
I already have a couple of these, but not the drivers.


At $20 it's cheap, if someone like to buy it... and share the drivers etc ;).

April 13th, 2016, 06:01 PM
Unfortunately it's just the Intel 386 in that box.

April 13th, 2016, 09:10 PM
Someone might buy it just for the paraphernalia (box, manuals, disks, Cyrix 486 case sticker).

April 13th, 2016, 09:12 PM

I recommend to write about 386 or 486 on another thread.

April 14th, 2016, 02:06 AM
Quest sells the Cyrix CX486DRX2-20/40GP 386>486 CPUs (new, but not in the original retail box) for $26 USD each.


These CPUs actually are ideal pin-compatible and easy upgrades for a PC or PC/XT that has an Intel InBoard 386 adapter - it allows that adapter to be upgraded from a 16MHz DX to an (effective) 33MHz (the max speed limited to 33MHz only by the oscillator that can be upgraded if you are good with a solder gun). The drivers are posed on http://vetusware.com/download/Intel%20Inboard%20386%20PC%20Drivers/?id=10861 and I have a PDF of the entire manual. I don't know what would happen if someone tried to do the same with the 25/50, but I suspect it either won't work or will still be limited to 33Mhz by the InBoard's stock oscillator.

Combine this with a CF HDD driven by an XT-IDE and you've got a screamin' 486-class PC or PC/XT capable of running everything up to Windows 3.1 well. A few of us here have done it: https://pcpartpicker.com/b/krYrxr