UMC 100%. Also fake cache.

I wonder if that is a board that came out of an OEM PC. I've got a couple of those boards but they have the sockets for the cache.

They are nice boards, but the soldered in cache is lame.

Looks like it is PC Chips (M912) after all. Real UMC with likely zero level 2 cache (depending on revision). Proud of my instincts.

http://www.elhvb.com/mobokive/archive/Oldman. … Chips/specs.htm
http://www.elhvb.com/webhq/models/486vlb3/m912fake.htm

Sigh.. 😒

cyclone3d wrote:

I wonder if that is a board that came out of an OEM PC.

No idea, found it on an auction.

Thanks for your part, guys.

cyclone3d wrote:

I wonder if that is a board that came out of an OEM PC

Looking into the matter further, I've found a similar board in an AcerMate 433s desktop, so you're probably right about the OEM thing.

an acer pc with fake cache? seems like someone did a mobo swap IMHO

Nah, the last one looks like M912 revision with real cache. Yep, those exist as well. You may be right, of course.

That "writeback" cache just screams fake. No way it was original board.

That's the PCChips M912 v1.7 with fake L2 cache. I had the M912 v1.7 with genuine L2 cache on it.

You can also remove the fake cache, solder on the sockets and jumpers for the L2 cache, install real L2 cache, and it should work, but, I believe a new BIOS chip and revision would also suffice since the one that's on there has a code on there that'll make the BIOS think there's L2 cache installed (pointing to the fake L2 cache).

''Write back'' is indeed very fake cache but i think the cache on the first picture is real, they just saved pennies on the sockets.

The Acer board was swapped, no way they sold boards like that to oem's and no way Acer would burn their hands on boards with fake cache.

I hate to burst your bubble, but, if there aren't any jumpers for the L2 cache or sockets, it's 100% fake.

PCChips M912 v1.7 w/ Fake cache

PCChips M912 v1.7 w/ Real cache

i think the original motherboard was swaped
i can't imagine a company like acer jumping into a legal battle and bad reputation for selling computers with fake cache..OR USING PCCHIPS AS a supplier for their pcs, besides acer used to build their own boards

bjwil1991 wrote:

That's the PCChips M912 v1.7 with fake L2 cache. I had the M912 v1.7 with genuine L2 cache on it.

You can also remove the fake cache, solder on the sockets and jumpers for the L2 cache, install real L2 cache, and it should work, but, I believe a new BIOS chip and revision would also suffice since the one that's on there has a code on there that'll make the BIOS think there's L2 cache installed (pointing to the fake L2 cache).

After installing real cache on two mobos with fake cache successfully, I can say that I didn't need to change the bios at all ! It just works ^^

I have the same exact motherboard but it has empty sockets installed instead of fake (or real) cache.
The problem that I have with this board ( apart that I need to populate the cache) is that it only recognizes RAM installed at the 30pin sockets, if I remove those SIMMS and install a RAM module in a 72pin socket it just refuses to boot.
I checked whether there's a jumper setting for that but it should supposedly recognize any RAM configuration on its own.
Any ideas?!

Make sure you use FPM RAM and not EDO as 486 have trouble running those.

Thanks I think that's it..
The modules I was trying were EDO but I tried some other modules that were also EDO just different make and it worked.
Since these pass the extended test should be left there or I'd better replace them with FPM type.?