You're not explicit about the platform, but I'm assuming 486 with VIP-IO given the options, and given the DX4-120 you seem to want to run it at 40MHz.

For a 486, best performance is acheived with VLB with zero wait-states. That usually means max 33MHz, maybe 40MHz very, very rarely 50MHz. At 40MHz, you need to get lucky to do zero ws. With 1ws at 40MHz, performance is lower than at 33MHz with 0ws.

Assuming your controller can handle 40MHz zero ws, VLB non-caching gives best perofrmane, so 2 or 4 (not sure 4 exists...). SCSI gives you the option to run a vastly non-period correct U160 15k rpm monster on an old VLB system. Haven't ever compared that to a CF card on IDE, but in both cases, it's access times that matter, so I suspect that CF card on IDE (with only passive converter needed) would give best performance at far lower price and noise. That said, I love my dual P3 U160 SCSI build and it is also really fast (with WinXP), so it wouldn't hurt at 486, but I doubt it would give added value over a much simpler solution.

Then VGA - same applies, for DOS at least, bus performance is key, so whatever runs at 40MHz 0ws will beat 40MHz 1ws regardless of controller. Assuming you have a lot to choose from, it's the usual ranking, so for DOS Ark1000, Tseng ET4000w/32 and UMC 85C418F with S3 DRAM (8xx series) following, although Advance Logic ALG is known to run at higher speed 0ws than most. In Windows, acceleration features matter, so S3 9xx and ATi Mach32 get better, as do Weitek and Matrox. For Windows and DOS, S3 VLB cards are generally the best bet.

dionb wrote on 2021-11-30, 21:21:

You're not explicit about the platform, but I'm assuming 486 with VIP-IO given the options, and given the DX4-120 you seem to wa […]
Show full quote

You're not explicit about the platform, but I'm assuming 486 with VIP-IO given the options, and given the DX4-120 you seem to want to run it at 40MHz.

For a 486, best performance is acheived with VLB with zero wait-states. That usually means max 33MHz, maybe 40MHz very, very rarely 50MHz. At 40MHz, you need to get lucky to do zero ws. With 1ws at 40MHz, performance is lower than at 33MHz with 0ws.

Assuming your controller can handle 40MHz zero ws, VLB non-caching gives best perofrmane, so 2 or 4 (not sure 4 exists...). SCSI gives you the option to run a vastly non-period correct U160 15k rpm monster on an old VLB system. Haven't ever compared that to a CF card on IDE, but in both cases, it's access times that matter, so I suspect that CF card on IDE (with only passive converter needed) would give best performance at far lower price and noise. That said, I love my dual P3 U160 SCSI build and it is also really fast (with WinXP), so it wouldn't hurt at 486, but I doubt it would give added value over a much simpler solution.

Then VGA - same applies, for DOS at least, bus performance is key, so whatever runs at 40MHz 0ws will beat 40MHz 1ws regardless of controller. Assuming you have a lot to choose from, it's the usual ranking, so for DOS Ark1000, Tseng ET4000w/32 and UMC 85C418F with S3 DRAM (8xx series) following, although Advance Logic ALG is known to run at higher speed 0ws than most. In Windows, acceleration features matter, so S3 9xx and ATi Mach32 get better, as do Weitek and Matrox. For Windows and DOS, S3 VLB cards are generally the best bet.

Thanks a lot bro!
Makes sense.

And I'd totally go SD or some other solid state stuff in any case, whether it's EIDE, UATA, SCSI, whatever.

I'd go with AMD 5x86-133 @ 160 (4x40).

Was UW SCSI already a thing in 94/95?
Isn't PIO mode slower than busmaster DMA (SCSI)?

retardware wrote on 2021-11-30, 23:27:

Was UW SCSI already a thing in 94/95?
Isn't PIO mode slower than busmaster DMA (SCSI)?

• Oh yes absolutely, even before, 1993 if I recall. I had copies of PC Professionale (the Italian version of PC Magazine) showing FAST SCSI-2 UW on their issues.
• Well, PIO mode 4 offers a 16.6 MB/sec speed, whereas with SCSI you get these speeds:

SCSI Type----------Clock Speed----------Bus Width---------Data Throughput
Original SCSI--------5 MHz------------8 Bits--------------5 MB/s
Wide SCSI----------5 MHz------------16 Bits--------------10 MB/s
Fast SCSI-----------10 MHz-----------8 Bits---------------10 MB/s
Fast Wide SCSI-------10 MHz----------16 Bits---------------20 MB/s
Ultra SCSI----------20 MHz-----------8 Bits---------------20 MB/s

You have to get to Fast Wide SCSI to exceed PIO Mode 4.

A late partial reply / opinion as asked for, hope it provides some value.

Firstly, every PIO mode sucks equally in my opinion. You are lucky if you manage to get 20% of the theoretical throughput. It bogs down the system while the cpu is busy waiting for the disk to execute single commands and send back the data. SCSI on the other hand can tag up to 255 commands and keep them in flight, with the drive executing them / returning the data in the most efficient order. Even without this command queueing, the fact that the system detaches from the drive as soon as the command has been sent, with the drive phoning back when it is done, makes the storage subsystem way more efficient. Same goes for bus master DMA transfers over IDE. No queueing, but much more efficient time wise. The disk sound changes to reflect the quicker transaction rate. PIO sounds klik-klak-klokkaklokka-klak etc where DMA transfers sound grrrrrt.

I tend to like an Adaptec 2940UW. It is fast and has a bios that can boot from the card. You can run anything from 50 pin 5MB/s to 68 pin 40MB/s devices on it.

I don’t know many 486 boards, but I like my Asus VL/I486SV2GX4. It seems to me as if this is also a popular choice on this forum.

In my limited experience, the picture quality of Trident ISA cards seemed better than that of Cirrus Logic and Realtek cards, in that order. But all of them are slow as snails, especially on resolutions above 320x200.

st31276a wrote on 2023-05-13, 07:01:

A late partial reply / opinion as asked for, hope it provides some value. […]
Show full quote

A late partial reply / opinion as asked for, hope it provides some value.

Firstly, every PIO mode sucks equally in my opinion. You are lucky if you manage to get 20% of the theoretical throughput. It bogs down the system while the cpu is busy waiting for the disk to execute single commands and send back the data. SCSI on the other hand can tag up to 255 commands and keep them in flight, with the drive executing them / returning the data in the most efficient order. Even without this command queueing, the fact that the system detaches from the drive as soon as the command has been sent, with the drive phoning back when it is done, makes the storage subsystem way more efficient. Same goes for bus master DMA transfers over IDE. No queueing, but much more efficient time wise. The disk sound changes to reflect the quicker transaction rate. PIO sounds klik-klak-klokkaklokka-klak etc where DMA transfers sound grrrrrt.

I tend to like an Adaptec 2940UW. It is fast and has a bios that can boot from the card. You can run anything from 50 pin 5MB/s to 68 pin 40MB/s devices on it.

I don’t know many 486 boards, but I like my Asus VL/I486SV2GX4. It seems to me as if this is also a popular choice on this forum.

In my limited experience, the picture quality of Trident ISA cards seemed better than that of Cirrus Logic and Realtek cards, in that order. But all of them are slow as snails, especially on resolutions above 320x200.

Wow thanks so much! Always appreciated.