If the tests were performed on a board with both PCI & VLB slots, then that is likely the reason of those results. Many PCI+VLB 486 boards tend to have poorer PCI VGA performance.

If the board is PCI only or VLB only, I doubt you will see much difference when using equivalent cards. For "fast" cards like the Millennium or even Trio64 I think the CPU will be the bottleneck, especially in SVGA modes.

Ahh.. so going with a PCI only SiS board rather than a VLB/PCI UMC board is a better idea? I have both.

It really depends what you want. I currently have a nice Cx5x86 build with PCI that is almost certainly faster than a VLB build would be (unless you had a very, very fast VLB video card and/or no PCI cards with decent DOS speed), but I'm actively looking for a VLB motherboard that would take the Cx5x86. Reason is simple: I don't run 486-era stuff for highest possible speed - I could just as well or better use my So4 or So7 systems for that. Those systems don't have VLB though, and the appeal of a fast VLB system is much higher for me than a PCI one.

dionb wrote:

I'm actively looking for a VLB motherboard that would take the Cx5x86.

I know that the Asus VL/I-486SV2GX4 does support the Cyrix 5x86 with a BIOS update.
I believe so does the Chicony CH-471A (rev. 3).
Some motherboard manufacturers referred to the CPU in their manuals as the Cyrix M9.

I guess that if you can find a VLB motherboard with an SIS 471 chipset, then you could probably swop out the BIOS of one of the above motherboards to gain Cyrix 5x86 support?

I would go with a PCI/ISA motherboard like the Luckstar LS-486 which supports the NEWER CPU’s like AMD 5x86-133-P75 over clocked at 160mhz.
( 4 x 40 ) @ 2.2volts

Those VLB motherboard usually have old bios that only supports 66mhz or 100mhz with Intel Overdrive CPU.
And those VLB slots are a lot of trouble . They are unreliable and hard to fit cards into.
Hard to find good VLB cards today too.
Barrel batteries
Dallas clock batteries.

The VLB motherboards require allot of work to get them working and even then they are limited in VLB card performance.

I never liked PCI+ VLB because of the design compromise. EISA + VLB is much better but very expensive and rare.

A straight PCI 486 with an easy to overclock AMD 486/133 running at 160 is a beast with a good PCI video card period. These days decent PCI cards are much cheaper to find then good VLB ones plus you get cheap and fast Ethernet and can still use ISA for sound. Cyrix 5X86 120's are better supported on PCI systems too.

Funnily enough i was exploring some of that stuff over the last few days.
Shared some results in another thread: Re: 3 (+3 more) retro battle stations
Also, the post before that big chart one compares the performance of ISA/VLB/PCI and ISA/PCI motherboards based on the same chipset.
Hope you find it useful.

PCI (the original variant) works at 33 MHz.
VLB works at the same frequency as CPU's FSB.

If you have a DX4-100, ie. 33 MHz FSB, then go PCI.
VLB may be better for CPUs with 40 MHz FSB.

Grzyb wrote:

PCI (the original variant) works at 33 MHz. VLB works at the same frequency as CPU's FSB. […]
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PCI (the original variant) works at 33 MHz.
VLB works at the same frequency as CPU's FSB.

If you have a DX4-100, ie. 33 MHz FSB, then go PCI.
VLB may be better for CPUs with 40 MHz FSB.

Downside: 40MHz (let alone 50MHz) VLB operation is far from trouble-free. Frequently you need to add a wait state >33MHz, that completely negates any advantage you might gain from the higher clock speed.

Of course, the challenge could be to find a board+VGA combination that will run at 40MHz (or even 50MHz) without that extra wait state, but that's a (big) goal on itself, and certainly not something to assume with any random combination.

I have yet to find a fast VLB graphics card that is actually faster than a slow PCI graphics card. VLB seems to max out at about 20 mb/s, with most cards doing only 10 mb/s. PCI on the other hand starts at 20 mb/s with the slowest cards and good cards do 45 - 90 mb/s. So I would always go for PCI if the choice is given.

VLB gets around the ISA limitations which is why it's considered fast.
But then so does PCI, and as a bonus you can run the next generation cards like the virge, Millennium, etc which are more Pentium era cards.

Really though I'd say VESA compatibility is more important as 486 isn't going to push these later cards. So If you really want to use the All in Wonder and it runs the games you want, then go for it.

Technically there's going to be little to no practical difference. The ISA / VLB / PCI card shootout thread above provides numbers to back that up, but so does common sense. You have two different local buses on a platform that is going to hit a CPU bottleneck before bandwidth gets to be much of an issue.

So, IMO.... go with VLB. You can do PCI on any number of different platforms. On a 486 you'll get a similar result either way, but PCI is more common and ordinary, and thus: boring. If you want to go faster, don't build a 486. There's zero practicality trying to turn a 486 into a speed demon. That's not what they do. If you want a 486, you want one because it's a 486, so you may as well use the platform that was so iconic to that era. Otherwise, why not just build a Pentium?

Im interested to see how an AM5x86-160 does on a VLB compared to a typical PCI board....

And it still might be pointless going VLB.

I think that ultimately a VLB card might show faster benchmark results but isnt going to help when testing high demanding games in a practical sense.

The higher bus speed wont help when the frames drop to single digits....