I did important discovery, moment ago, i try ATI Mach 64 PCI as primary video card and EMS without any parameters is working fine. So there some problem with Geforce 6600 AGP with combination with this board and EMS, card is fine for sure, i used it for years and removed it from other computer.. I tried before multiple AGP and PCIe (Ati X600) cards before os its not only Nvidias problems.
I can also tell that S3 Virge and Trident PCI are not working with this board, at least not when Nvidia G6600 AGP is plugged, but ATI MAch 64 does, so probably they are not working at all..

If is ATI 64 mach as primary card, it doesnt matters, which card is PCI-e slot, i didnt tested AGP, but it would be with high probabality the same. Maybe problem is not if card is PCI or AGP/PCI-E but Video Bios size, because these old cards, have only 32 KB, modern cards have 64KB or more..

I tried to write UMBPCI guy, if is possible to add VIA 880 support, no luck:
For the VIA 880 chipset there is no information available how to activate the upper memory.

Srandista wrote:

BTW, could you please try ESS Solo-1 on very similar board (4CoreDual-SATA2) in Win 98? I'm able to get sound on DOS 7.1, but not in Win 98 😒

Got the same problem on my Asus P5VD2-VM SE (VIA P4M900+VT8237S), driver refuses to load after install under Windows 98SE but the card works very well under MS-DOS 7.1. Please let me know if you ever find a solution to your problem.

Kamerat wrote:

Got the same problem on my Asus P5VD2-VM SE (VIA P4M900+VT8237S), driver refuses to load after install under Windows 98SE but the card works very well under MS-DOS 7.1. Please let me know if you ever find a solution to your problem.

With 4CoreDual-VSTA its working fine, i dont remember if i used in-build Win98 drivers, or some from web, but it worked without problem, i used second PCI slot from bellow.

ruthan wrote:

With 4CoreDual-VSTA its working fine, i dont remember if i used in-build Win98 drivers, or some from web, but it worked without problem, i used second PCI slot from bellow.

Tried my card in the other PCI slot with same result. I decided to try out the WDM driver instead and it actually works (used the VxD driver in my previous attempts).

Kamerat wrote:

Srandista wrote:

BTW, could you please try ESS Solo-1 on very similar board (4CoreDual-SATA2) in Win 98? I'm able to get sound on DOS 7.1, but not in Win 98 😒

Got the same problem on my Asus P5VD2-VM SE (VIA P4M900+VT8237S), driver refuses to load after install under Windows 98SE but the card works very well under MS-DOS 7.1. Please let me know if you ever find a solution to your problem.

Yeah, at the end I find a solution... But it required change of motherboard... So there that...

After some research, I decided, that likely culprit with missing sound in Win 98 is chipset, and after I change VT8237S for VT8237A, everything started working immediately. So after my testing and confirmation from Kamerat, I can say, that ESS Solo-1 on boards with VT8237S either don't work at all (in my case with 4CoreDual-SATA2) or only with WDM drivers (with Kamerat's Asus P5VD2-VM SE). With VT8237A chipset, there isn't any problem at all, both VxD and WDM drivers works just fine on Win 98.