Set the jumpers for DX2-66.

dominusprog wrote on 2024-04-19, 08:48:

Set the jumpers for DX2-66.

Thanks, I will try.

Really exciting! The Pentium OverDrive 83MHz works!

Glad it worked out! You have a very nice setup there.

And I´m confident 1MB L2 cache will be capable to cache the whole lot of 4MB RAM 😉

385387386 wrote on 2024-04-23, 13:58:

Really exciting! The Pentium OverDrive 83MHz works!

Is this a modified Pentium Overdrive? Without fan normally it will run only on 33MHz, so with multiplier 1. That would be slower than a DX2-66, but still good to install Windows XP, haha.
Where did you get those Winbond W241024AK-15 chips from?
Good luck for the replacement job. Maybe it will be a good idea to install sockets.

EDIT: The exact same serial number on all 12 chips looks a bit suspicous. I am afraid you are going to replace fake cache with fake cache.

CoffeeOne wrote on 2024-04-23, 18:14:

Is this a modified Pentium Overdrive? Without fan normally it will run only on 33MHz, so with multiplier 1. That would be slower […]
Show full quote

385387386 wrote on 2024-04-23, 13:58:

Really exciting! The Pentium OverDrive 83MHz works!

Is this a modified Pentium Overdrive? Without fan normally it will run only on 33MHz, so with multiplier 1. That would be slower than a DX2-66, but still good to install Windows XP, haha.
Where did you get those Winbond W241024AK-15 chips from?
Good luck for the replacement job. Maybe it will be a good idea to install sockets.

EDIT: The exact same serial number on all 12 chips looks a bit suspicous. I am afraid you are going to replace fake cache with fake cache.

I found the chip on a B2C website (taobao).

Yes, can not rule out all the chips are still fake. I'll try. The corresponding 32dip sockets are really really hard to find, maybe I can use double 16pin dip socket instead.

I'm thinking use pencil trick may get the frequency back. Very interesting to see running Windows XP on a 486 platform. And I predict the OS should be very slow even frequency on track

And the Pentium Overdrive 83 is little bit odd, there's no marks on the backside.

dominusprog wrote on 2024-04-23, 15:23:

Glad it worked out! You have a very nice setup there.

Yeah. Thanks.

I will find an old AT keyboard to get through the post to check whether the board's old BIOS can display the Pentium OverDrive correct or not, since the post stuck there with keyboard error.

majestyk wrote on 2024-04-23, 16:04:

And I´m confident 1MB L2 cache will be capable to cache the whole lot of 4MB RAM 😉

Maybe 256MB RAM will also covered 😉

385387386 wrote on 2024-04-23, 23:49:

majestyk wrote on 2024-04-23, 16:04:

And I´m confident 1MB L2 cache will be capable to cache the whole lot of 4MB RAM 😉

Maybe 256MB RAM will also covered 😉

...in write-back mode, of course 😒

majestyk wrote on 2024-04-24, 09:01:

385387386 wrote on 2024-04-23, 23:49:

majestyk wrote on 2024-04-23, 16:04:

And I´m confident 1MB L2 cache will be capable to cache the whole lot of 4MB RAM 😉

Maybe 256MB RAM will also covered 😉

...in write-back mode, of course!

Glued 6 small heatsinks on the top.

majestyk wrote on 2024-04-24, 09:02:

majestyk wrote on 2024-04-24, 09:01:

385387386 wrote on 2024-04-23, 23:49:

Maybe 256MB RAM will also covered 😉

...in write-back mode, of course!

I'm not sure it can really support write back mode.

385387386 wrote on 2024-04-26, 23:44:

Glued 6 small heatsinks on the top.

Install a 20x20mm fan on the heat sink, just to be on the safe side.

385387386 wrote on 2024-04-26, 23:44:

Glued 6 small heatsinks on the top.

Does it now run at 33 or 83MHz?

CoffeeOne wrote on 2024-04-27, 14:44:

385387386 wrote on 2024-04-26, 23:44:

Glued 6 small heatsinks on the top.

Does it now run at 33 or 83MHz?

33MHz, I try to short the GND dot and Sensor dot with a wire, but it failed to boot. Any way to work around to get 83MHz back? Thanks.

dominusprog wrote on 2024-04-27, 13:50:

385387386 wrote on 2024-04-26, 23:44:

Glued 6 small heatsinks on the top.

Install a 20x20mm fan on the heat sink, just to be on the safe side.

Okay, I'll install a fan on top.

385387386 wrote on 2024-04-26, 23:49:

majestyk wrote on 2024-04-24, 09:02:

majestyk wrote on 2024-04-24, 09:01:

...in write-back mode, of course!

I'm not sure it can really support write back mode.

I´m sure this UMC PCI chipset does support L2 write back mode. But if it is capable of cacheing 256MB RAM in write through mode, the cacheable area will probably be 128MB in write back mode.

majestyk wrote on 2024-04-28, 06:38:

385387386 wrote on 2024-04-26, 23:49:

majestyk wrote on 2024-04-24, 09:02:

I'm not sure it can really support write back mode.

I´m sure this UMC PCI chipset does support L2 write back mode. But if it is capable of cacheing 256MB RAM in write through mode, the cacheable area will probably be 128MB in write back mode.

That's great, 256MB memory on the way.