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Alaris Cougar video card woes

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First post, by jasa1063

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I just got an Alaris Cougar motherboard with MR BIOS. I am running it at the default 25MHz FSB speed. I cannot get any of the two VLB video cards I have to work. One is Cirrus Logic 5426 and the other is a Cirrus Logic 5429. Both video cards work just fine in my Alaris Leopard motherboard. Cirrus Logic video cards are usually very compatible. I have tried changing the jumpers for the VLB settings at JP4, JP5 & JP8. I took the back plate off both video cards to make I could seat each VLB card all the way down into the VLB slot. I also used DeOxit5 in both slots. Everything I have tried so far does not work. I am currently running with a Micro-Labs ET4000 True Color ISA video card set to 0WS. I would expect the video performance to be at around 6MB/s with the ISA bus set to 12.6MHz, but I am only getting 2MB/s. I am unable to get any faster performance than that despite changing the BIOS settings. At this point I have run out of ideas. Any suggestions would be greatly appreciated.

Thanks!

Reply 1 of 3, by jasa1063

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Well I feed a bit stupid about the ISA video card performance. It never occurred to me that when I jumpered the Turbo Switch header and on the motherboard that actually put the it into slow speed mode. I removed the jumper and I am now getting an expected 6MB/s performance. Still no luck with a VLB video card, but I can live with the ISA video card performance for now.

Reply 2 of 3, by BitWrangler

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This seems to be seen often on 386/486 VLB boards when used with a 386 class, the theorising goes that it only works for very early revisions of VLB, it is suggested that ATI MACH 32 cards are most likely to work, but those are a bit spendy to try on a whim.

I have a related system, board built by IBM microelectronics, and labelled a "Cobalt" board, but not the "Cobalt AT" that the Cougar is, most obviously because it's not an AT, but some LPX type... anyway, that is theoretically VLB with a VLB extension for the riser, but was supplied with only an ISA riser, and no mention of VLB is to be found in existing documentation. Leading one to suppose that it wasn't working as well at it was supposed to and they didn't want to support it.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 3 of 3, by jasa1063

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As a next best thing option, I installed a Diamond SpeedStar 64 2MB ISA video card that I put aside for another project, but this one seems to be a better use case. I am happy with the results so far. Windows 3.11 performance is really great. WinBench 3.11 gives a score of 34 million and I can certainly live with that!

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