VOGONS


First post, by Great Hierophant

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I am thinking of making an offer on this motherboard :

http://www.ebay.com/itm/Name-Brand-486-Board- … #ht_4640wt_1139

No real identification is given for the motherboard, but since it is identical with these, I assume it is the same.

http://motherboards.mbarron.net/models/486vlb3/m912fake.htm

http://motherboards.mbarron.net/models/486vlb3/m912v17.htm

Now, the motherboard has just about everything I want in a 486 motherboard, socket 3, a 3V coin battery clip, support for turbo and virtually every 486 processor available, support for 3.3-4V processors, 72-pin SIMMs, up to 1MB WB cache, and LBA support. While it uses AMI's Win BIOS, it is not the end of the world.

I know that the offered motherboard does not use fake cache because the cache is socketed, whereas fake chips are soldered. Still, are there any gotchas I need to be concerned with if I buy and use this board? The Red Hill Guide does not spare these boards with fake cache, so I wonder if it had real cache would the situation be any different? The silkscreened UMC UM8498F & UM8496F seems to be a real UMC chipset. The chips with a sticker label seem to be a PC Chips chipset in disguise?

http://redhill.net.au/b/b-bad.html

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog

Reply 1 of 3, by DonutKing

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It does look like a PC-CHIPS M912 board. If the cache is real I don't see how you can go too far wrong, its certainly got plenty of features.

They were always a 'budget' brand so it might have some funny problems. I had an M919 with the fake cache, and even with cache disabled, I'd sometimes get some strange errors and lockups (not frequently but they did happen). Whether the M912 is comparable to the M919 I'm not sure.

If you are squeamish, don't prod the beach rubble.

Reply 2 of 3, by feipoa

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Did somebody say 486?

That particular eBay seller is pretty good with his communication and isn't a cheap skate about accepting reasonable offers. Better yet, he will usually ship USPS First-class mail to Canada if you accept the item as-is. There is a small point of concern in his auction listing though, "Photos in this listing may not show the exact item we will ship."

On to the board now, I do not have any personal experience with this board, but my first impressions are:

1) 3 VLB slots? From my understanding, only 2 VLB slots can be used simultaneously and often the good boards only have 2 VLB slots due to this foresight.

2) The fact that this board also had fake cache (on some editions) is somewhat concerning. I'd probably want to see the bottom of the board to ensure that there are at least traces going to the cache.

3) I second what DonutKing said about the M919. PC Chips's main weakness is not necessarily in their ability to source decent components, but in producing well-tested BIOS firmware.

4) Cache looks real.

5) If you have been unable to find any posts where someone has tested an M912, you might be taking a gamble. Sometimes you get lucky.

P.S. This happens only once, so I figured I'd annouce it, this is my 586th post! w00t!

Plan your life wisely, you'll be dead before you know it.

Reply 3 of 3, by Great Hierophant

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Three VLB slots was the maximum, and that was really pushing the spec hard. In theory, with one VLB board, you can run the system bus at 50MHz, but the Intel 486 DX/50 was not considered particularly reliable. With two slots, you could run the bus at 40MHz, but that required a top quality board. Three slots could run no faster than 33MHz, but with three slots filled, there were risks of instability.

I would not use more than 2 VLB slots anyway. Other than video and IDE or SCSI, nothing else I would conceivably use would improve the performance. Nothing else on a multi-I/O board is going to tax even an 8-bit IDE bus.

Without looking at it, the cache is real. If it were fake, not only would the "cache" but also the BIOS would be soldered. It is cheaper to solder chips directly instead of soldering sockets and mounting them. Fake cache boards were all about saving every possible last penny.

"Photos in this listing may not show the exact item we will ship."

Good point to ask about that. Often there are minor variations between motherboards like PCB color or the size and shape of passive components, but I wouldn't touch a suspicious board.

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog