Jo22 wrote on 2022-07-21, 10:27:

rasz_pl wrote on 2022-07-21, 05:51:

16bit ISA is around 5MB/s.

At 8,33 MHz ("ISA").
That number is from vcfed, I suppose. 😉

I meant thats the number fastest ISA VGAs reach on overclocked bus. I dont remember ever seeing one passing 6MB/s. Thats with rep movsw, port IO would probably top out lower.

pshipkov wrote on 2022-07-20, 19:25:

It is implied that for ISA bus we are talking Adaptec AHA-1542CF.

I was a SCSI guy back in the ISA era, and yeah, Adaptec 1542 is the go-to. It's bootable, DMA-capable (although ISA DMA can be twitchy), and supported by anything SCSI from that era.