VESA/ISA/PCI Board - What to use the VESA for?

[Raven]

I have two boards that have ISA, PCI, and VESA on the same board. They have three PCI, four ISA, and one of the ISA is also a VLB. I love quirky variety systems like this, and would like to build a box from one of my boards here. I'd like it to be a higher-end 486 than my ValuePoint, as it seems to be lacking for some of the last few DOS games out there. Since this board likely supports Am5x86 properly (ValuePoint will only run it at 100mhz), I can get one running at 133 or maybe 166/180mhz.. theoretically it's possible that with the right board and cooling you could get 200-266mhz out of it. That should provide the processing power. What I was wondering is what to put in the VESA slot. Should I use it for video? It will be at least at 33mhz, possibly 40 or 50 depending on what the board allows me to do - if it goes up to 40 or 50 obviously it should be a bit quicker than PCI provided I'm using era-appropriate PCI cards. Assuming it sits at 33mhz though, is there any advantage to the VLB over PCI or vice versa? VLB has a unique connection to the 486 buses, so I was thinking it might perform better if both buses are operating at 33mhz.

Anybody know? Or shall I conduct experiments? xD

 

[Tetrium]

Runing VLB at 40Mhz might prove problematic for any PCI card. That and theres no guarantee your VLB card will work without adding extra waitstates, further limiting the speed bonus provided by increasing the fsb.

Personally I'd use my best VLB cards for VLB-only mainboards.

If you're runing at 33Mhz then it shouldn't be realy problematic runing both VLB and PCI cards. I reckon both are about the same speedwise BUT it's a helluva lot easier getting decent PCI cards

 

[Raven]

Well having stripped a pile of really boring 486s I ended up with a few interesting motherboards and a ton of VLB cards, so I do have the stock. Personally I'm a big fan of Trident, which is what I use in most of my DOS machines (PCI and VLB, ISA too, I have them all from Trident..). I have some Cirrus Logic cards for VLB that I haven't used yet that should outperform the Trident cards by a mile if I understand correctly. I don't have anything fancy like a Tseng on hand or I'd use that.

I realize that using VLB cards at higher-than-33mhz speeds only works for a few cards without adding the wait states, and I figured I'd just try each video card I had if I end up with a bus that quick until finding one that worked. As for PCI, I was unaware that the system bus affected it, even on a 486 mobo - can someone confirm that PCI cards bugger out with >33mhz bus speeds on a 486?

 

[Unknown_K]

If you have a PCI/VLB board then just use the PCI, mixing will cause problems and PCI cards will be faster.

If you must use a VLB card pick a video card since most will work at 40mhz speed just fine. Most VLB network and SCSI controllers don't like anything above 33mhz and will hand at 50mhz.

 

[Raven]

Well I have tons of boards, PCI/ISA, PCI/ISA/VLB, VLB/ISA, and just ISA. I just find the versatility of a computer with three slot flavors interesting.

I have so many 486 boards and Pentium boards, the Pentium ones 'cuz I stripped many Pentium boxes for parts when people were getting rid of them left and right, and 486s just 'cuz I love 'em.

 

[Unknown_K]

I have a ton of 486 machines, (ISA, VLB, EISA, MCA) and many more cards of those types then machines. While having an all in one is convenient, having to deal with a buggy board and crashes trying to mix VLB and PCI is not worth the trouble. My only PCI/VLB board is going to be sold in a system one of these days just to get rid of it.

Heck even sticking to just VLB has drawbacks when you try using 3 VLB cards in the same machine (video, scsi, network) because it causes a bottleneck between the CPU and its cache since VLB bus inteferes. PCI is the most boring since it is still "modern" but you have the most options and cards are cheap.

If you have not noticed from my sig, I collect all kinds of cards for Nubus, EISA, ISA, VLB, MCA. Outside of Nubus you can find a 486 board with any of the other slots (which is another reason I like 486 systems).