IDE Controller - Single vs dual fifo?

A friend has a Mystique/Rainbow Runner setup and everything seems hunky-dory. Graphics OK, connections fine. Grabs stills OK, but refuses to capture any video sequences,
although sound is captured!

DMA is enabled on drive. Win95 OSR2, standard drivers and so on.

Just read an article on the Mystique/RR
setup, saying this might be an IDE controller problem.

It says that under Device Manager> Hard disk controllers - Dual fifo *must* be listed / enabled.

Well I've tried everything, including sniffing around the BIOS, and no joy, regardless of what I change the Primary and Secondary IDE controllers still say '(single fifo)'.

Could there be some obscure registry setting that enables it?

On my own PC with Marvel G200 (more or less same RR on board?) 'dual fifo' *is* listed. My card works fine. So perhaps the writer of the article is right. If so, how the heck do
you change from single to dual 'fifo'; is that possible?

Tried searching for a solution, or even some info on dual and single fifo settings with IDE controllers; but to no avail.

I'm not new to PCs but I have to confess to never having paid much attention to dual or single 'fifo' before. Never needed to!

Thanks for any help on this.