there is one more question: many 486 speedsys screenshots reported the bios to have Y2K bug, does this mean that they can never set the date to the 21st century, or just unable to jump from 12-31-1999 to 01-01-2000?

It won't jump from 1999 to 2000 but some other date like 1973. It works just fine when set to today.

About the 486 PCI boards... I don't have any preference. I just use what I have. The fastest are most probably with UMC8881 chipset.

Have a look at the specs of the Luckystar LS-486E (there were different revisions) - refer LuckyStar LS486E rev.C2 and Cyrix 5x86@133

Also the PC Chips M919 motherboard and the Biostar MB-8433UUD motherboard.
These two were used as test motherboards in the "The Ultimate 486 Benchmark Comparison" - refer The Ultimate 486 Benchmark Comparison.

Personally, I like the Asus PVI-486SP3, but this motherboard doesn't run well at high FSB frequencies (since there is no divider in the BIOS for the PCI bus) and it's also a bit slower than PCI/ISA only motherboards.

In answer to your last question.
When the date rolls over to 01/01/2000, then it will actually roll over to 01/01/1900 (or some other date in the past).
However, most motherboards since the early 90's had calendars that go up to 2099 (some went to around 2050 I think, not sure).
So, if you set your date now to 2016, it won't be a problem until 2099. But, I'm not worried about that at all, since I doubt that I will live to see that millennium.

The calendar issue can be more serious on some BIOS versions than others. Many times a TSR is necessary to adjust date in correlation to the wrongly set BIOS date.
I use this utility:

http://Www.daqarta.com/y2kure.html

Unfortunately, the affected Award Bios is widespread.

LuckyStar LS486E - LuckyStar LS486E rev.C2 and Cyrix 5x86@133 or Biostar MB8433UUD-A.

Biostar mb-8433uud-a, also supports FSB up to 60Mhz.. but it not easy to obtain.

I could recommend you two motherboards that I'm currently using:

- A-trend ATC-1425B. It has SiS-496-497 chipset, up to 512kb cache, PS2, triple voltage options (3.3, 5 and 4 volts), supports any 486 and 5x86 CUPS, has 50mhz bus option, has PS/2 mouse connector, 4 ISA and 4 PCI slots (I have noticed any irregularities in terms of graphics card support), button battery, etc.

- ZIDA 4DPS (so called tomato), which has all the features described above, but only 3 ISA and 3 PCI slots (it's a tiny mobo) and just two voltage options as far as I know; it also has just two memory sockets.

jesolo wrote:

Have a look at the specs of the Luckystar LS-486E (there were different revisions) - refer LuckyStar LS486E rev.C2 and Cyrix 5x8 […]
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Have a look at the specs of the Luckystar LS-486E (there were different revisions) - refer LuckyStar LS486E rev.C2 and Cyrix 5x86@133

Also the PC Chips M919 motherboard and the Biostar MB-8433UUD motherboard.
These two were used as test motherboards in the "The Ultimate 486 Benchmark Comparison" - refer The Ultimate 486 Benchmark Comparison.

Personally, I like the Asus PVI-486SP3, but this motherboard doesn't run well at high FSB frequencies (since there is no divider in the BIOS for the PCI bus) and it's also a bit slower than PCI/ISA only motherboards.

what? PVI-486SP3 has no pci divider? i had expectations on this board aswell. not all boards have their dividers set in bios, could it be hard jumpered? and have you tried if it works with pci cards at 50fsb?

the ls486e seems to support only 256kb of cache, no.

the 8433UUD, yes i had expectations on this too, but pretty hard to find.

and are there other big at boards made in the later days of 486 like the pvi-486sp3, rather than the mini ones? while mini ones can do the job, bigger ones surely seem to have better quality.

Aquarius MB-4DUPM, can hit 66MHz FSB and supports every CPU I have thrown at it. Also has VLB. Good luck finding one. I think most of them used an RTC anyway. Basically it is a bit like a PC Chips M919 without the weird cache and a different BIOS, uses the UMC UM8881/8886 chipsets.

MSI MS-4144, I'd love another one of these but will probably never get one as my Pentium 66 and Pentium OverDrive have taken its place. Coin Cell, SiS chipset, very fast. I do not believe it supports the 5x86 processors, at least, not out of the box, though it does offer the voltage they need so it may be possible to run them anyway, mine gave up before I could test. It was very (almost ridiculously) fast with an AMD Am486DX4-100 WB installed though and I never really had compatibility issues with any cards. My 3C905 would freeze Windows at boot if you didn't set the PCI up correctly in the BIOS, but compared to many boards it was relatively trouble free. I seem to think it supported up to 1024K of cache.

The BioStar people talk about is a good option and is well documented.

Personally, I prefer VLB for the 486 and it usually ends up being faster anyway (as I tested) and I find that by the time you want to go further than the DX4, the Pentium is a better platform anyway, PCI is more at home on a Socket 5 system too. However, there is a certain novelty to running a PCI 486 with the fastest CPU you can jam in there.