I would almost bet that the Bios was intentionally set up to defraud people by selling them a 486 as a Pentium.

basically, I suspect that the CPU type will always be shown as a P54CM regardless of what CPU is actually used.

Nah, a reputable company like PC Chips would never do that.

dionb wrote:

feipoa wrote:

dionb wrote:

First I upgraded it to a Voodoo3-3000, then added more memory. And more. And more. It only had two 72p SIMM slots, but every time I gave it a bigger module, it [...]

Could you let me know which UM8881F/8886BF -based motherboard you were able to get a Voodoo3 working in? To-date, I have only been able to get a Voodoo3 working in a 486 motherboard containing a SiS 496/497 chipset.

Will dig down in my old documentation, but not sure I actually wrote down anything about this one... around the same time I was doing a memory performance benchmark on every Socket 5 / 7 chipset I could get my hands on, which I did document pretty well. This 486 was just a one-off joke. No idea what I did with the board, but I certainly haven't had it since moving in 2008...

Is it possible that you've mistaken this motherboard for one containing the SiS 496/497 chipset, like the Tomato 4DPS or Luckystar LS486E?

Koltoroc wrote:

I would almost bet that the Bios was intentionally set up to defraud people by selling them a 486 as a Pentium.

basically, I suspect that the CPU type will always be shown as a P54CM regardless of what CPU is actually used.

WOW

and if I update the BIOS with this one: http://th2chips.freeservers.com/m915/, it should fix the problem. It is right?

Other question: does anybody know what model of chips I should use to replace cache?

Yes... That bios will solve the problem.. find a 27c512 chip and program it with bios. I can do it for you... Only postage costs, no extra money.. send me the 27c512 and I will do it... I have that mobo... It is top... Very good.. it could be nice replace the hard wired cache size jumpers for real ones if you want more than 256kb... I will post tonight the correct if for cache or eBay for 256kb cache tag ram 486

feipoa wrote:

[...]

Is it possible that you've mistaken this motherboard for one containing the SiS 496/497 chipset, like the Tomato 4DPS or Luckystar LS486E?

Definitely not one of those. It was dark green, backed with antistatic plastic, and absolutely tiny - no wider than an ISA slot was long, about 1.5x longer than it was wide. And pretty certain about the chipset, given the memory thing.

Note when I say the Voodoo3 3000 PCI "worked", I mean it displayed desktop under Windows XP. I didn't actually try to run any games or other 3D applications with it.

dionb wrote:

feipoa wrote:

[...]

Is it possible that you've mistaken this motherboard for one containing the SiS 496/497 chipset, like the Tomato 4DPS or Luckystar LS486E?

Definitely not one of those. It was dark green, backed with antistatic plastic, and absolutely tiny - no wider than an ISA slot was long, about 1.5x longer than it was wide. And pretty certain about the chipset, given the memory thing.

Note when I say the Voodoo3 3000 PCI "worked", I mean it displayed desktop under Windows XP. I didn't actually try to run any games or other 3D applications with it.

Memory is a funny thing. What did your notes reveal?

feipoa wrote:

dionb wrote:

feipoa wrote:

[...]

Is it possible that you've mistaken this motherboard for one containing the SiS 496/497 chipset, like the Tomato 4DPS or Luckystar LS486E?

Definitely not one of those. It was dark green, backed with antistatic plastic, and absolutely tiny - no wider than an ISA slot was long, about 1.5x longer than it was wide. And pretty certain about the chipset, given the memory thing.

Note when I say the Voodoo3 3000 PCI "worked", I mean it displayed desktop under Windows XP. I didn't actually try to run any games or other 3D applications with it.

Memory is a funny thing. What did your notes reveal?

Nothing.

I came upon some lists of 486 motherboards that I dug up at some computer fairs, and a couple of forum posts bragging about getting Windows XP running on a 486 board, but nothing more detailed I'm afraid.

dionb wrote:

Once you have determined how much RAM it will accept, you can do the same with cache. Start with a low amount (eg. 16MB) and do a cache benchmark. Increase to 32, 64, 128 and 256MB and rerun the bench each time. As soon as you're outside cachable area, you'll see the difference.

What program do you recommend for cache benchmark? Where Can I get it?

In phil's dos benchmarks there's a program called CACHECHK, that tests the cache, the mode (WT or WB), the amount of cache, the speed compared to the ram and the amount of ram cached.

HI weldum!!

Thanks for the info!!

Hi again !!

I've received some SIMM modules and 486 CPUs yesterday. Now I can answer my previous questions (and not speculate as we have done here, until now):

1- The mainboard supports modules SIMMs greater of 16 MBs. At this moment the board for testing purpose has
SIMM 0: 32 MB
SIMM 1: 32 MB
SIMM 2: 16 MB
SIMM 3: empty

and it's working properly.

2.- I've tested 4 diferents 486 CPUs: DX-33, SX-25, DX2-50 and DX2-66. The BIOS detects right, without any problems. I read the manual again and the manual does not make references to support SX2 CPUs: only SX, DX, DX2 and DX4 CPUs. This statement is wrong:

I would almost bet that the Bios was intentionally set up to defraud people by selling them a 486 as a Pentium.

basically, I suspect that the CPU type will always be shown as a P54CM regardless of what CPU is actually used.

I understand that board BIOS doesn't support for SX2 CPUs, but they are working properly if you configure like SX CPU

3. The cache is fake. I've tested with phil's DOS benchmarks
4.- Perfomance: I've read in some posts here that the perfmance of this board is poor if you compare with others: MSI...I've got a MSI board (Some questions about MS-4144). I haven't got much free time but, I've pass all test availabel in phil's DOS benchmarks. (the same configuration: identical CPU, identical VGA (matrox millennium II 8 MB - PCI, identical memory modules, and identical HD (Compact flash) ). Well, I'm very surpraise. The PCChips with fake cache outperforms my MSI-4144 in all phil tests. I understand that are very simple tests, but....It's very curious

Regards

Aren't yours cache chips to far to the left ??? every boards i've seen with dip28 cache chips, they where layed out to the right, leaving the blank space to the left

Hello.
@muon - would you be so kind and share some info regarding the jumper settings you've made for each 486 you used on this board.
I have the exact model of motherboard with 2 models of 486 : one is DX2 50 from intel and the other one is DX4 100 from AMD.
As for cache, my board have real cache chips.
Thanks mate