A summary of the mid-to-end of line 486 motherboards "research" early in the thread.
The effort started with building a long list of motherboards.
Most of them got discarded based on various criteria.
15-ish made to the hands-on examination phase.
Most of the results are shared in the thread, but got too big and hard to follow, so putting together this compact summary split in 6 sections, as follows:
--- 486 class CPU at 160MHz
The sweet spot of all things 486.
Easy to achieve with Am5x86-133 processors + air cooling.
Plenty of motherboards handle it well, but there are 3 that stand out:
Asus PVI-486SP3
One of the most flexible 486 assemblies. ISA, VLB, PCI buses. Rock stable and hustle free package.
Best at offline compute - (de)compression, encoding/decoding, 2D/3D rendering, image editing, spreadsheets, etc.
Its PCI interface is slightly behind the curve at DOS interactive graphics. Comes back on top of any ISA/PCI board when paired with fast VLB video cards like Ark1000VL or S3 Trio64.
Its PCI graphics are top notch at accelerated Windows GUI and in line with the best ISA/PCI mobos (which excel at that with more modern PCI cards like Matrox Millennium).
Best on-board IDE controller - period 😀
Asus VLI-486SV2GX4
The best 8-bit pixel pusher. Fastest board for DOS interactive graphics. Especially if paired with fast VLB video cards like Ark1000VL or S3 Trio64.
With S3 Trio64 it is on par with the best ISA/PCI boards at accelerated Windows GUI. But only with 16-bpp and up to 1024x768.
Lacks in offline compute.
When paired with strong VLB EIDE controller (like Promise EIDE2300 Plus) it takes a PCI UltraDMA/33 tech to outdo it at disk i/o.
Biostar MB-8433UUD-A
The best implementation of UMC's UM8886BF late 486 chipset.
Probably the fastest ISA/PCI board out there. Also - rock solid.
Its on-board IDE controller and drivers are lacking, but the PCI interface provides options for Ultra DMA class upgrades.
Limited out-of-the-box L2 cache size. Also, extremely picky about cache chips that can hit the tightest BIOS timings.
If 1024Kb L2 cache mod is applied the board pulls even further ahead - best offline compute, best Quake 1 score, best at Windows GUI (on par with LuckyStar C2), second only to VLI at DOS interactive graphics.
--- 486 class CPU at 180MHz
Several motherboards can do it on a test bench.
Few can do it well.
Two are worth putting inside a PC case.
Building such a computer is not trivial, so selecting the right components makes big difference.
LuckyStar LS-486E rev:D
Clearly the best option in this cathegory, but only after replacing the on-board 15ns L2 cache chips with 10 or 8 ns ones.
It was in a group of late and fast ISA/PCI boards ticking great at 160MHz, but that was it - one of many.
Apparently there is plenty of built-in padding that allowed it to scale much better than anyone else past the 160MHz.
Very fast, very stable and just works.
Handles well Voodoo3 which at this CPU speed allows decently performing 3D accelerated graphics.
For reference - Voodoo3 seems to be the best option for 3D accelerated graphics on a 486-class hardware.
For some reason does not like Gotek floppy emulators. Looks like inherent issue unrelated to overcloking, etc.
Biostar MB-8433UUD-A
Similar to LSD - fast and solid. Scales slightly worse than LuckyStar D.
UMC's IDE drivers lead to instabilities and cannot be used = less-than-ideal IDE performance.
Not a big deal - Promise UltraDMA-100 PCI to the rescue.
Voodoo3 incompatibility is a drawback. Voodoo2 is still a great option but requires extra PCI slot. SLI makes the situation even worse.
PC-Chips MM919 v3.4B/F
With 1024Kb L2 cache module this is the fastest system at 180MHz.
Still, leaving it in third position because of the next factors:
- Voodoo3 incompatibility.
- 1Mb L2 cache modules are very rare.
- If base frequency is above 40MHz automatic PCI bus divider kicks-in. To work around that Turbo has to be OFF until POST completes.
- UMC IDE drivers issues like with UUD.
Honorable mention - Chicony CH-471B revision 2 - truly unique assembly.
1024Kb L2 cache, ISA/VLB, on-board Appian ADI/2 EIDE controller, clockgen with 60/66 MHz frequency.
So far the only ISA/VLB board in the 3x60 department.
--- 486 class CPU at 200MHz
Very few boards can do this well at 3x66MHz, more can handle 4x50MHz.
3x66 is better in general than 4x50 despite the requirement for PCI bus divider.
LuckyStar LS-486E rev:D and Biostar MB-8433UUD-A do best at 3x66.
Finding the right set of L2 cache chips for the Biostar UUD board can be particularly unpleasant.
Chicony CH-471B rev.2.0 is another impressive assembly - the fastest classic ISA/VLB motherboard out there. It actually outdoes some of the later 486 assemblies in some disciplines by relying on Ark1000VL ticking at cool 66MHz.
Few SiS 496/497 PCI/ISA boards with 1Mb L2 cache can handle reliably 4x50 and follow very close behind the two above.
Then everybody else (at 4x50).
Honorable mention - Chicony CH-471B revision 2 - truly unique assembly.
1024Kb L2 cache, ISA/VLB, on-board Appian ADI/2 EIDE controller, clockgen with 60/66 MHz frequency.
Handles reliably the 200MHz (3x66) which makes it the most scalable and because of that the fastest ISA/VLB motherboard.
Even better - without bus dividers. Yes, thats right - Ark1000VL VLB ticking at 66MHz.
Impressive.
--- Pentium Overdrive at 100MHz
This one is very easy - Asus VLI-486SV2GX4.
While it is awesome, nothing is truly perfect.
There is one drawback - when L1 cache is set to WB mode any configuration with more than one memory module (in the first slot) can be unstable in some situations. The motherboard cannot recognize modules bigger than 32Mb, so this is the limit.
Close second are LuckyStar LS-486E rev:D and Biostar MB-8433UUD-A.
They do better at accelerated Windows GUI and some offline compute tasks.
--- Cyrix 5x86 at 133MHz
I don't have direct experience with these CPUs.
Adding the section for completeness.
There are 2-3 threads talking about that.
LuckyStar LS486E rev.C2 and Cyrix 5x86@133
The World's Fastest 486
The Ultimate 486 Benchmark Comparison
Users Ph4ntom, Rad and Feipoa contributed most of the information there.
Performance seems to be slightly lower than Am5x86@180MHz in most tasks.
Looks like the best boards are again LuckyStar LS-486E and Biostar MB-8433UUD-A.
At least Feipoa and Rad have assembled PCs around this configuration, so it will be up to them to clarify.
--- Cyrix 5x86 at 150MHz
There is limited information about the subject.
Cyrix 5x86 120(FSB40,60) 150MHz(FSB50) Speedsys result
Hypothetical 5x86
The Ultimate 486 Benchmark Comparison
Also, several other mentions here and there.
Mostly Feipoa's contribution based on his Biostar MB-8433UUD-A setup.
Does not feel like a long-term stable solution, but still worth mentioning it for completeness.
Performance seems to be approaching Am5x86@200MHz and POD100 levels in the different tasks.
---
This is what i got so far.
Closing the 486 chapter with this post but reserve the right to revisit the notes if new facts emerge.
Also, starting to investigate some options for long-term stable 200MHz system. I think it is possible, so will see ...