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386 with VLB, suggestions?

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First post, by DNSDies

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I recently came into a 386/486 hybrid that has a footprint for a VLB slot that isn't populated. I'm planning to install a slot for it (I have a few), and I'm debating on what to install in this new fast slot on what I plan to be a 386DX 40mhz machine.

Option 1: QD6500a VLB controller card. The obvious bonus being very fast drive speed, but also using XT-IDE to take full advantage of it. The negative to this is being stuck with an ISA video card. Luckily, I have a WD90C31 1MB ISA card, so it'll at least be the fastest slow video card.
Option 2: Continue to use an ISA controller card, and instead put a Diamond Stealth 32 VLB (Tseng ET4000/w32p). Benefits - very fast video card, but detriment of slow ISA controller card and needing to keep a network card to boot the XT-IDE bios.

What should I do?

Reply 1 of 28, by Deksor

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Is it this board ? http://www.win3x.org/uh19/motherboard/show/2134

Because the unpopulated slot isn't a VLB slot from what I've been reading.
Now maybe I'm wrong, but at least check that the voltages match a vlb slot ^^

Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative

Reply 2 of 28, by H3nrik V!

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Doesn't VLB only work with 486 and later?

Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀

Reply 3 of 28, by pan069

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H3nrik V! wrote on 2020-10-20, 06:02:

Doesn't VLB only work with 486 and later?

If I'm not mistaken, VLB is more a chip set feature than a CPU feature. I have a 386/486 board with VLB. At the moment I have a 386/33 on it.

Re: 386 motherboard recommendation

Reply 4 of 28, by DNSDies

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Deksor wrote on 2020-10-20, 05:51:

Is it this board ? http://www.win3x.org/uh19/motherboard/show/2134

Because the unpopulated slot isn't a VLB slot from what I've been reading.
Now maybe I'm wrong, but at least check that the voltages match a vlb slot ^^

That's the one. It seems to be VLB. 112 pins, MCA footprint, silkscreen says "Local 1".
I'll double check the voltage pins, but it really looks like VLB.
Here's a picture from Phil's Computer Lab, you can count out the pins and see the silkscreening:
https://www.philscomputerlab.com/fx-3000.html

Reply 5 of 28, by Deksor

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Yeah it has a slot that's physically compatible, but the way they hide it or unpopulate it, the fact it's not described as vlb in the manual and things people have found point that it might not be that.

Again maybe they're wrong, so yeah double checking is the best solution here ^^

I'd love to see what it truly is 😁

Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative

Reply 6 of 28, by H3nrik V!

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DNSDies wrote on 2020-10-20, 06:41:

That's the one. It seems to be VLB. 112 pins, MCA footprint, silkscreen says "Local 1".
I'll double check the voltage pins, but it really looks like VLB.

Wikipedia says that VLB is 116 pins?

Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀

Reply 7 of 28, by DNSDies

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yeah, if it's not, no big deal. I only wanted this as a pure 386 anyway and it would save me an hour of desoldering the empty holes and soldering in a new connector.
If I want a super speed 386/486 with VLB, I have an Alaris Cougar for that.

H3nrik V! wrote on 2020-10-20, 06:52:

Wikipedia says that VLB is 116 pins?

With 4 key pins.

Reply 8 of 28, by gbeirn

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H3nrik V! wrote on 2020-10-20, 06:02:

Doesn't VLB only work with 486 and later?

Somehow lost my post.....

It’s basically a direct electrical connection into the 32 Bit memory bus of the 486.

It can be adapted to later systems like the Pentium but is hit or miss since that requires a bridge chip usually from PCI->VLB since the Pentium has a 64 Bit memory bus.

Since a 386 had the same memory bus, it will work albeit slower with possibly no performance advantage.

At its most basic level a 486 is nothing more than a higher clocked and tightly integrated (CPU/FPU/Cache) 386z

Reply 10 of 28, by dionb

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gbeirn wrote on 2020-10-20, 06:58:
H3nrik V! wrote on 2020-10-20, 06:02:

Doesn't VLB only work with 486 and later?

[...]

Since a 386 had the same memory bus, it will work albeit slower with possibly no performance advantage.

Oh, it still gives a performance advantage, even when nerfed down to 16b with a 386SX, simply by running at full clock speed with lower latency than ISA. Even on a 386, graphical stuff in particular is bottlenecked by ISA performance.

I have an Alaris Leopard with an IBM "486SLC2" which is nothing more than a fast clock-doubled 386SX. It has VLB despite only having a 16b external bus. Doom benches a good 10% faster on VLB than on ISA, even with this narrow bus.

It does seem to matter how the chipset handles it though, as reports with OPTi 495 chipset 386/486 boards seem to indicate no improvement of VLB vs ISA. I have one, but only very slow socketed 386 CPUs (16, DX20), so can't really check myself.

Last edited by dionb on 2020-10-21, 07:22. Edited 1 time in total.

Reply 12 of 28, by BinaryDemon

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I’d be worried after all that work that it turns out to be some proprietary 32bit local bus and you can’t find anything compatible with it.

Check out DOSBox Distro:

https://sites.google.com/site/dosboxdistro/ [*]

a lightweight Linux distro (tinycore) which boots off a usb flash drive and goes straight to DOSBox.

Make your dos retrogaming experience portable!

Reply 13 of 28, by jesolo

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Over the years, I've only managed to acquire 3/486 VLB hybrid motherboards utilising the OPTI 495XLC chipset. One was my original Jetway J-402B motherboard and the other one was a Dataexpert EXP3406.
Unfortunately, I've never managed to get any VLB graphics card to work on those motherboards with either an AMD386DX-40 or a Cyrix 486DLC-40 installed.
I recently acquired another 3/486 VLB hybrid motherboard (an A-Trend, also with the same OPTI 495XLC chipset) and I'll see if I have more luck with that one. Would be nice to be able to pair my Cyrix 486DLC-40 with a VLB graphics card to be able to squeeze a bit more frames out of Doom.

Interestingly, based on benchmarks I've performed between a hybrid motherboard and just a standalone 386 motherboard, there does seems to be a performance hit on these hybrid motherboards (in particular, these OPTI495XLC motherboards).
I've read somewhere that VLB cards don't always work on hybrid motherboards if you have a 386 CPU installed, but it should work with a 486 CPU installed. I guess this also comes down to chipset and BIOS implementation.

I don't believe there is any difference in I/O performance between a 16-bit controller, versus a 32-bit VL-Bus I/O controller under DOS - it might be a different story under Windows 3.1x, but then you need to have the appropriate drivers installed and 32-bit support enabled to make use of that.

Reply 14 of 28, by mpe

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Yes. In DOS unless you use modern VESA games and linear framebuffer there is very little difference between 16bit and 32bit buses as many DOS apps just use 16bit writes. Even 32bit games like DOOM.

Furthermore , many early VL-Bus VGA controllers (such as GD542x series) are 16bit only on the host interface side and they interface to 32bit VL bus using transceivers which creates a bottleneck and they don't benefit from 32bit bus.

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Reply 15 of 28, by kixs

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I have good experiences with 386 and VLB cards. But it's some time since I've used them and might not remember if there were any glitches... It's still on my to-do list to test every board I have with different 386 type cpus and see which board is the best (386DX, 486DLC, 486DRx2, 486SXL, 486SXL2). I'll probably use the most compatible VLB card Genoa Phantom S3 864 2MB.

Last edited by kixs on 2020-10-20, 12:44. Edited 1 time in total.

Requests are also possible... /msg kixs

Reply 16 of 28, by Anonymous Coward

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I can't speak for the 495XLC, but I had a hybrid 495SX that definitely worked with VLB graphics cards when 386DX/486DLC was installed. I remember the boost being much more noticeable with the DLC.

Support for 16-bit operation should be built into the VLB spec. I'm not sure which cards don't work, but I tested VLB graphics in my Alaris Leopard, and it worked with every single one of them (for those that don't know, I have a lot). I could possibly see disk controllers being a little more problematic though..especially the SCSI ones.

Even if a VLB graphics card uses an older 16-bit controller chip, it should still benefit quite a bit from the increase in bus speed.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 17 of 28, by Bancho

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I actually put together a 386 VLB machine today. I'm using a Cirrus Logic 5428 VLB VGA Card and a VLB Super I/O Card based on a promise chipset. I have very little experience with 386 stuff so this is new grounds for me, but so far its working. I was testing Wolf3d and Monkey Island on it and they were working fine. I need to sort out the cmos battery as there isn't one currently. And i need to learn about the board and tuning it.

This is the board

bHUBHHHl.jpg

and the machine as it stands

JzpkIODl.jpg

Reply 18 of 28, by kixs

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Bancho:

I have that one too. Only my has a socket for the CPU so I can swap different CPUs for testing. I also got a CPU removal tool recently to make swapping easy 😀

Requests are also possible... /msg kixs

Reply 19 of 28, by quicknick

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Got this board (a pair of them, actually) and the VLB slot doesn't work even with a 486 installed (haven't tried a 386 as it requires soldering a PQFP one which I don't have).
As a matter of fact, in the elhvb description it is stated that the VLB doesn't function. Strange board.

Looking at the photos above, I wonder if the 486 socket doubles as a 387 socket when there's a 386 soldered...

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