http://www.uncreativelabs.de/th99/m/A-B/33258.htm

It looks an awful lot like this one. The onboard cache looks like it might be fake (it looks like the chips might say "WRITE BACK" on them). That's probably why there's real cache in the COAST slot.

Looks like a PCChips M507, Socket 7 Motherboard.

http://motherboards.mbarron.net/models/pcchips/m507.htm

I have one of these myself and it looks near identical, apart from the IDE & Floppy ports which are white on yours, instead of black.

That board, if the same, does indeed have fake cache hence the requirement of a COAST module.

Although not officially supported, it can run an AMD K6-2. I've got a K6-2 500 running at 300MHz, though BUS speed is underclocked to 50MHz.

PTherapist wrote:

Looks like a PCChips M507, Socket 7 Motherboard. […]
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Looks like a PCChips M507, Socket 7 Motherboard.

http://motherboards.mbarron.net/models/pcchips/m507.htm

I have one of these myself and it looks near identical, apart from the IDE & Floppy ports which are white on yours, instead of black.

That board, if the same, does indeed have fake cache hence the requirement of a COAST module.

Although not officially supported, it can run an AMD K6-2. I've got a K6-2 500 running at 300MHz, though BUS speed is underclocked to 50MHz.

I thought that the max multiplier is 3x and max bus speed is 66Mhz? How do you cpu running 300Mhz on that motherboard?

Anonymous Coward wrote:

http://www.uncreativelabs.de/th99/m/A-B/33258.htm

It looks an awful lot like this one. The onboard cache looks like it might be fake (it looks like the chips might say "WRITE BACK" on them). That's probably why there's real cache in the COAST slot.

One difference I noticed was that the ram banks are the opposite. The first bank is closer to the edge of the motherboard. Also it says V1.1 in corner of my motherboard and that web page says it is V2.0
if there is no on board cache, does that mean that coast module cache is slower than on board cache would be?
When booting it says 512Kb pipeline burst cache. It does not say anything about write back cache.

Baoran wrote:

I thought that the max multiplier is 3x and max bus speed is 66Mhz? How do you cpu running 300Mhz on that motherboard?

K6-II/III treat a multiplier of 2x as 6x.

Koltoroc wrote:

Baoran wrote:

I thought that the max multiplier is 3x and max bus speed is 66Mhz? How do you cpu running 300Mhz on that motherboard?

K6-II/III treat a multiplier of 2x as 6x.

Chompers Extended (CXT) and later does. The original K6-2 (Chompers) does not.

I don't really have need to make that faster though. I am just curious about the coast module and if coast module cache is slower than if it had real cache on board. (If it has fake cache)
I assume this is one of those motherboards which you should not use more than 64Mb of ram because of the cache?

Sorry to break your happiness, but this board is in really bad shape. Look at the pins on the UMC chip to the left of the PCI slots. There's a huge deep scratch in the PCB, and the chip pins are crushed. This probably means that COM1/COM2/LPT1/LPT2 will have problems.
I'd try to straighten up or remove those crushed pins completely (last resort) if I were you. Shorted pins are not okay!

I didn't really pay anything for it. At least it is working now. I don't have a serial mouse to try with it, but if I needed com ports, I assume I could disable on board com ports and just put an ISA I/O card there?

Yes, you could do that. Do not go overboard with powerhungry CPUs with This board. The VRM transistors run pretty hot (at least on my pcchips) and these capsules are not meant to dissipate too much.

It came with that pentium 120Mhz that is in the picture. I think the cpu is a socket 5 version. Only thing I changed was that I did put those two 32Mb memory modules there while it came with 4x4Mb memory modules.

Baoran wrote:

I don't really have need to make that faster though. I am just curious about the coast module and if coast module cache is slower than if it had real cache on board. (If it has fake cache)
I assume this is one of those motherboards which you should not use more than 64Mb of ram because of the cache?

I've got 128MB RAM installed in mine - however I don't have a COAST module installed, so I have no idea if it has the 64MB issue. I never had a COAST module back in the day, as I was unaware of the fake cache issue and just assumed that it's slow performance was normal. 🤣

Having a K6-2 at 300MHz installed, even without cache, makes it run quite nicely and mine can handle late 1990s DOS and some late 1990s/early 2000s Windows gaming. I did have the CPU clocked faster than 300 at one point, but it lead to stability issues most notable in DOS games, whilst Windows didn't care much beyond occasional erractic Serial Mouse behaviour.

elod wrote:

Do not go overboard with powerhungry CPUs with This board. The VRM transistors run pretty hot (at least on my pcchips) and these capsules are not meant to dissipate too much.

Yeah I noticed that too, particularly when I touched them by mistake once - ouch! Mine ran for years like that though and still shows no signs of stopping.

I have another pc with P2 cpu for later games. I am going to use this one purely with dos. I don't actually need pentium for those older dos games, so I might switch the motherboard with 486 or 386 later. but at the moment I am bit limited because of many old parts I had stopped working recently.
I could have put 2x32Mb + 2x16Mb there, but there really isn't dos games that would take advantage of that and not knowing if the chipset limitation of 64Mb applies to my motherboard I decided to just put 64Mb.

I'm pretty sure that Amptron and PCChips are the same company (as well as a few others).

My motherboard says "MG product" and has MG serial number that you can see in the pictures, but it is very close to both of those motherboards from Amptron and PCChips with only minor differences like memory banks being in different order and some chips are different brand.

Also JP4 which is below JP3 in my pictures seem to be missing from both of the manuals, so I have no idea what that is for.