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ATI Mach32 VLB versus Mach64 ISA

I

icecom3

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Jun 17, 2011
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I was hoping to collect some opinions on this. I have an ATI Mach32 (1993) 1MB card that uses a VLB slot (faster than ISA) and I wanted to replace it with a card that shows higher resolution in 16bit color. So I ordered an ATI Mach64 (1996) 2MB card, but it uses an ISA slot. I already know I am going to get a better resolution, but now I am worried about performance.
I play mainly high end dos games (i.e., thunderscape, Warcraft II, Mechwarrior II) and a few games designed for windows 95. I know that Mach64 supports dos gaming in terms of dedicating memory, just worried about performance in general.

So although it’s a newer card, will the downgrade from VLB to ISA kill me? Also, I added this ISA card to the same VLB slot on the mainboard but I don’t know if that makes any difference.
 
Since you have them both test each out and see which you like better. High end DOS games don't use high resolution nor 24 bit color so either card will work.
 
You would have been better off upgrading your Mach32 to 2MB (or just getting another 2MB VLB card). Despite the name, Mach32 actually uses a 64-bit path to memory, except when 1MB is installed then it halves the bandwidth to 32-bit. Mach64 also has a 64-bit memory path, and is a 64-bit chip internally. That makes is *slightly* faster than a mach32. I own many of these cards, and I never noticed much of a difference in speed when memory type and capacity are equal. I think the two main advantages of using the Mach64 is the improved DOS performance in the VRAM versions of the card, and better memory expansion (VRAM model can go to 4MB). In your case though, you'd really be better off with anything VLB since you use games. The ISA cards are really only useful when you have a system without VLB slots. If you're using VESA video modes, you really want VLB. Pretty much any 2MB card will do. S3 and Tseng were popular with gamers back in the early-mid 90s. ATi wasn't that bad, but was less common since it was proprietary and expensive.
 
Yeah, the point about ISA is that its biggest issue is that it was probably fine for the 5170, but its bandwidth is way out of step for 386 and later CPUs.
 
Ok, yeah that VLB slot makes a huge difference in speed. I used the original Diablo as a stress test and it bombed pretty bad with the Mach64 ISA. When I put the Mach32 VLB back in it actually played well. I was surprised it even loaded on my Gateway 2000 4DX2, with P83 overdrive. I followed ACs advice and bought an unused Mach32 with 2mb just to get those resolutions I want. So I know now that nearly every DOS game and many win95 games will play on this rig.
 
I never even knew what a VLB bus was until I started restoring this computer. But now I am a fan of these slots. Right now I have an ISA controller card managing my 4gb drive. I got 1 extra VLB slot left so I am debating if I should put a HD controller card there or a nice sound card.
 
Sound cards are all 16 bit not VLB. I would suggest a VLB I/O + HD card with a "newer" 2GB drive to speed things up. There are nice VLB SCSI cards with floppy ports but they cost more, and you will need an ISA I/O card.
 
The problem with VLB was that it was quriky. Resource allocation was often "well, it depends on the manufacturer". Originally it was intended for video, but was expanded to other high-bandwidth applications, mostly SCSI and hard disk controllers. And it was pretty much locked into the 80486. But when all you had was ISA, EISA or VLB, VLB was the best choice.

PCI with its automatic resource allocation is much, much better, if not more complicated.
 
PCI was smarter, and much newer. For VLB you had 1 -3 slots that interupted the CPU/cache/RAM bus with data using speeds of 25/33/40/50 Mhz, kind of a mess. Each VLB card had to be rated at the speed of the CPU bus and the drivers for all of them had to play nice. PCI did away with variable speeds and had its own BUS not coupled to the CPU directly. I kind of liked EISA, much esier to see what was going on and configuring cards. VLB was geared to home machines and EISA for servers so one side had a ton of video cards and the other a ton of SCSI and networking products.
 
PCI wasn't that much newer--PCI 1.0 dates from 1992; the same year that the VESA Local Bus specification came out. The problem was that there was a fair amount of complexity and bureaucratic loopholes for vendors to jump through, so it was mostly deployed in high-end systems It took longer to get into consumer-level 486 boxes.

VESA Local Bus was pretty much a temporary kludge.
 
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