ratfink wrote:

Any ideas for a fix [apart from use another monitor!].

Use another graphics card 😉
The Matrox cards have problems with some VGA games. I'm not sure if Lemmings 2 is affected (haven't tried it myself), but if the flickering doesn't occur with a different VGA card, it's most probably the Matrox.

Nice system, btw 😀

Right, I will try another card when I get time. Any views on a good card for DOS games? AGP or PCI if possible - there's no free ISA slots left in this machine so if ISA is better for DOS games then I will have to change the mobo.

I can try the following easily [from the spares box] but if there's anything substantially better I'll try to get one:

S3 Trio 2X/3D 4MB AGP

Ati Mach64 1MB or 2MB PCI

I've got a few Voodoo's but I specifically wanted to see what the V1 can do so I can't use them. Also got a Trident ISA but like I said, no free ISA slots.

The two cards you mentioned should be fine - if the ATI PCI card passes the test, you could install it together with the Matrox and switch whatever card you need in the BIOS setup.

ISA bandwith is too low for graphing and you can't have linear frame buffer acces, you should stay with PCI
I keep a S3 ViRGE/DX PCI 4MO for games that don't work with Voodoo4

I've tried an ATI Rage Pro AGP,and an ATI Mach64 PCI - neither make any difference. I also tried with the V1 disconnected and CPU cache disabled. Still get the flicker. I've got a less sophisticated monitor so I'll try that next.

You should try with a small sceen (15 in)
Lots of old games use 320x200 since it is the only 256 colors mode which can be set in the same way for all graphic cards before vesa.

Ho hum, I tried my 17 inch monitor [15 inch visible], but no joy.

I don't think, it's 320x200 as such causing a problem, as Quake runs on either monitor at that scale [albeit from Windows 98].

Maybe I'll try it in Dosbox [on a faster machine!], and see what happens.