zuldan wrote on 2024-08-04, 06:52:

Trying to fix the flashing screen (bottom half) problem in Keen 5 with this card.

I think it's just an issue with Diamond's cards. Gona has documented it on his website.

It's a shame really, because Diamond branded Virge cards tend to have great image quality. But on the plus side, I think it's mostly the Keen games that are affected.

Joseph_Joestar wrote on 2024-08-04, 07:57:

zuldan wrote on 2024-08-04, 06:52:

Trying to fix the flashing screen (bottom half) problem in Keen 5 with this card.

I think it's just an issue with Diamond's cards. Gona has documented it on his website.

It's a shame really, because Diamond branded Virge cards tend to have great image quality. But on the plus side, I think it's mostly the Keen games that are affected.

Thanks Joseph. I forgot about Gina’s website. I’ll just have to live with it. The card works extremely well with everything else I’ve thrown at it. Glad I found the 4MB version in an old PC 😉 Crazy prices on eBay for a 4MB ($200 plus).

zuldan wrote on 2024-08-04, 06:52:

Trying to fix the flashing screen (bottom half) problem in Keen 5 with this card.

Did you try enabling the SVGA compatibility mode in Commander Keen? That setting enables a workaround that will slightly reduce performance, but avoids the most common incompatibility beteween SVGA cards and Commander Keen by not relying on the video memory to wrap around after 256K.

mkarcher wrote on 2024-08-04, 10:43:

zuldan wrote on 2024-08-04, 06:52:

Trying to fix the flashing screen (bottom half) problem in Keen 5 with this card.

Did you try enabling the SVGA compatibility mode in Commander Keen? That setting enables a workaround that will slightly reduce performance, but avoids the most common incompatibility beteween SVGA cards and Commander Keen by not relying on the video memory to wrap around after 256K.

+1
This usually fixes those types of issues. If it doesn't there is always the K1n9_Duk3 patches. https://pckf.com/viewtopic.php?f=4&t=6192

Interesting that all the Diamond Virge types have this issue but not the others. Wonder what did Diamond did to their bios that would cause it.

Horun wrote on 2024-08-04, 16:36:

Interesting that all the Diamond Virge types have this issue but not the others. Wonder what did Diamond did to their bios that would cause it.

Probably the S3 Virge has a control bit that limits the addressable video memory to 256KB. Commander Keen requires that this limit is active in EGA graphics modes. It seems the Diamond BIOS does not enable the "256KB only" mode in standard EGA/VGA modes. If it is just a control bit that is not correctly set, it would be a simple fix. You might also just try the BIOS from a different S3 ViRGE DX card. These BIOSes are usually completely interchangable, as there is nearly no way to "customize" a ViRGE/DX PCI card. You might for example try the BIOS from a Hercules Termintor 3D/DX. That BIOS initializes the ViRGE/DX chip at a sensible clock of ~70MHz, whereas some cheap OEM ViRGE/DX cards use a generic ViRGE classic BIOS that initializes the core clock to 45MHz, which yields awful 3D performance unless you change the clock using some 3rd-party utility.

mkarcher wrote on 2024-08-04, 19:27:

Probably the S3 Virge has a control bit that limits the addressable video memory to 256KB. Commander Keen requires that this limit is active in EGA graphics modes. It seems the Diamond BIOS does not enable the "256KB only" mode in standard EGA/VGA modes. If it is just a control bit that is not correctly set, it would be a simple fix. You might also just try the BIOS from a different S3 ViRGE DX card. These BIOSes are usually completely interchangable, as there is nearly no way to "customize" a ViRGE/DX PCI card. You might for example try the BIOS from a Hercules Termintor 3D/DX. That BIOS initializes the ViRGE/DX chip at a sensible clock of ~70MHz, whereas some cheap OEM ViRGE/DX cards use a generic ViRGE classic BIOS that initializes the core clock to 45MHz, which yields awful 3D performance unless you change the clock using some 3rd-party utility.

Thanks ! I was thinking one of the other bios would work fine. I have a Cardex Virge 4Mb and a Diamond Virge ST 3D 4Mb and think I will try a bios swap just for kicks if the EDO memory is same speeds...

mkarcher wrote on 2024-08-04, 10:43:

zuldan wrote on 2024-08-04, 06:52:

Trying to fix the flashing screen (bottom half) problem in Keen 5 with this card.

Did you try enabling the SVGA compatibility mode in Commander Keen? That setting enables a workaround that will slightly reduce performance, but avoids the most common incompatibility beteween SVGA cards and Commander Keen by not relying on the video memory to wrap around after 256K.

I didn't try that. Didn't even know that option existed. I must be the biggest Keen noob. The card works perfectly now.

Really appreciate everyone else's response. I have a much better understanding now of why this issue occurs.

zuldan wrote on 2024-08-05, 09:05:

I didn't try that. Didn't even know that option existed. I must be the biggest Keen noob. The card works perfectly now.

No problem with being a noob. I'm glad I could help you.