Al's Geek Lab delivers you -- my IBM 5160, complete with original 256 motherboard still in play, delivers you a slice of DooM running at ~20FPS.

Yes, it is running with an upgrade card - an Intel Inboard/386 PC Yes, I rodded the hell out of that too, with a ParrotyError 4MB ram expansion piggyback board and an IODATA PK486 Blue Lightning 3 (IBM/Cyrix) CPU which clocks in at 96MHz!

Thats so cool, I wonder how much further you can push it!

The next bit of modding is to /reduce/ the clock speed actually. I am going
to change the crystal on the Inboard to 20MHz (down from 32MHz). This means I'll be able to run the BL3 CPU at 80MHz rather than 96MHz. I think that
80MHz will be better than the 96MHz because of the bus timing on the InBoard.

Is the processor on the piggyback board socketed or not? If it is I wonder you could replace it with......

Yes, the CPU is socketed. I don't think there is much more performance to
get, regardless of the CPU - this is because of the 8 bit bus on the IBM motherboard.

Also I wonder what performance would be like using a super XT motherboard runs at a higher clock speed than the XT? Bumping the ISA bus speed up to 10Mhz would surely speed things up quite a bit!

Looks like you already understand the above issue. If I changed the DMA controller and other support chips on the IBM 5160 mainboard, I could likely get the ISA bust to at least 8MHz. I did so on my

... A toast -- To a kinder gentler echo

It is indeed a kinder, gentler echo :). Lovely people!


hyjinx // Alistair Ross
Author of 'Back to the BBS' Documentary: https://bit.ly/3tRINeL (YouTube) alsgeeklab.com

--- Mystic BBS v1.12 A49 2024/05/29 (Linux/64)
* Origin: Al's Geek Lab -=- bbs.alsgeeklab.com:2323 (21:1/126)

Is the processor on the piggyback board socketed or not? If it is I w you could replace it with......

Yes, the CPU is socketed. I don't think there is much more performance to get, regardless of the CPU - this is because of the 8 bit bus on the IBM motherboard.

I largely agree, though if you could use something with more internal cache that whatever the current CPU has, it could make up for the bus at least a little....... if it works with that board.... and the board supports whatever voltage it needs.... I doubt that this will make much difference though.

Looks like you already understand the above issue. If I changed the DMA controller and other support chips on the IBM 5160 mainboard, I could likely get the ISA bust to at least 8MHz. I did so on my

Oh seems your last sentence was cut off :(

Upgrading all the chips on your 5160 sounds like quite the commitment! Are they mostly socketed or are we talking desoldering with a re-work soldering station here.

... Jesus Saves - and Dalglish scores from the next attack!

--- Mystic BBS v1.12 A49 2024/05/29 (Linux/64)
* Origin: 2o fOr beeRS bbS>>20ForBeers.com:1337 (21:2/150)

Yes, it is running with an upgrade card - an Intel Inboard/386 PC
Yes, I rodded the hell out of that too, with a ParrotyError 4MB ram expansion piggyback board and an IODATA PK486 Blue Lightning 3
(IBM/Cyrix) CPU which clocks in at 96MHz!

Man I love stuff like that!! When the system architecture was so straightforward you could just brainslug a generations-ahead CPU on there and off it goes. Getting that Mac/Amiga Accelerator experience without any dedicated facility.

Retro computing kicks ass.

--- Mystic BBS v1.12 A49 2024/05/29 (Linux/64)
* Origin: 2o fOr beeRS bbS>>20ForBeers.com:1337 (21:2/150)