I have the same board in my 386 (just called ISA-386). It's a great board!

AFAIK there is no way of upgrading the cache on this board. On a 386 it wouldn't matter much anyway in terms of performance boost. Even on a fast 486 going from 256k to 1024k only gives 1-2% performance increase.

Thank you!

I am courious why do you think this board is so good? I find it really neat and good quality overall, but is it about exceptional chipset, performance, reliability, upgrade options, layout, etc?

I surely like the CPU that is not soldered but socketed.

It doesn't have a built-in battery, they came with external ones from the factory, meaning NO battery corrosion! Another thing is stability and build quality. Its performance is quite good and I've had no reliability issues. Upgrade options are a bit limited compared to later boards (for instance you must switch out the clock crystal if you want to upgrade the CPU to 40mhz) and cache is max 64kb on the board itself which is enough for a 386. A neat feature (which you will probably never use) is the RAM expansion card that allows you to install up to 64MB of RAM:

Picture shows the ISA-486C memory card, but it is very similar.

Here is my build with the board: Time for a new 386 build with some nice components

Indeed, memory upgrade card seems to be an overkill in this kind of machine, I guess I'll even limit myself to 4mb.

Very cool setup you got there.

I will use my CT1600 as well, accompanied by Music Quest PC MIDI interface.

For graphics - Western Digital WD90C00-JK which I got fully expanded to 1mb RAM. I guess it will do just as good as any other card on a 386. Maybe later I will upgrade to some tseng ET3000AX or similar.

How do we know for certain the board can't be upgraded to 256kb cache? It looks very similar to the ISA-386C (which supports 256). Are the jumpers to set the cache size from that board present on the 33-64K?

Anonymous Coward wrote:

How do we know for certain the board can't be upgraded to 256kb cache? It looks very similar to the ISA-386C (which supports 256). Are the jumpers to set the cache size from that board present on the 33-64K?

There are no options for that amount of cache on my ISA-386C. TH99 also states 64kb cache as max. You arent confusing it with the ISA-486C? That board can do 256kb

I was pretty sure that there was a member on vogons that upgraded their 386C to 256kb. I want to say that it was Amigaz. The SiS Rabbit chipset does support 256kb.

I reviewed the board and I'm almost sure there is np jumper related to cache amount. Do mi guesses would be either:

1. The change is detected automatically by the chipset - possible sis 85c310 controller feature?

2. Cache amount is limited board design, irrespective of chipset potential features.

considering 64k is literally printed on the board, I would bet the farm the board will only do 64k.

Yep, on the other hand what would be the reason to limit cache size in a high-end motherboard if its chipset fully supports 256K? Also, why would they put cache in sockets and not just solder them? Usually this happens when there are some upgrade options. Just my assumptions.

I have 256K/32MB working on my SiS Rabbit-based 386 board. Is this an older Rabbit revision?

I will check the exact designations when back at home.

BTW - do you think I only need to exchange those 10 dip pieces, ot there are some other parts requiring replacement (like those 64k-p23-3 and 64k-p23-4 dips - I don't know their purpose).

Also, why would they put cache in sockets and not just solder them?

SRAM is highly sensitive to electrostatic discharge (easy to fry). They're in sockets so they can be easily replaced.

The change is detected automatically by the chipset - possible sis 85c310 controller feature?

I'm skeptical of this, since I have the chipset data sheets. Pretty sure a jumper would need to be set, or a bridge soldered.

feipoa wrote:

I have 256K/32MB working on my SiS Rabbit-based 386 board. Is this an older Rabbit revision?

and whats the speedup from that? i guess it would only help running something big like windows 95 :>

I hope with this upgrade I can get 120 FPS playing Alley Cat or Boulder Dash as for now these games seem to skip frames - but this may also be caused by the fact my 386 system lacks numeric co-processor. It's the next thing I BADLY need to get 😉

TH99 lists the max RAM on the 386/33-64K as 8MB without the memory expansion board. Can you confirm whether or not it works with 4MB SIMMs? If it only accepts 8MB, then a cache upgrade would be pointless anyway.

mrau wrote:

feipoa wrote:

I have 256K/32MB working on my SiS Rabbit-based 386 board. Is this an older Rabbit revision?

and whats the speedup from that? i guess it would only help running something big like windows 95 :>

Doesn't matter that much to me. The excitement for me comes from taking the board to the limit.

I was wondering if the BIOS on this motherboard could be updated or replaced?

It's some version of AWARD Modular Bios which looks something like this:

You can swap BIOSes on older boards, but at the very least they will need to be chipset specific. MR-BIOS makes a great replacement, but it's pretty difficult to track them down these days.