ASUS Media Bus (aka not-PCI-64-bit)
I'd picked up an old motherboard from an eBay auction and had seen a PCI slot with an extension.
Here I was thinking it was PCI 64-bit...
I grabbed the 64-bit SCSI card that I'd installed in my G4 Graphite Macintosh (which has a suite of 64-bit slots) and quickly realised it wasn't what I thought it was!
Ok.. it doesn't fit... let's look closer?
From the photos above, it doesn't take a genius to work out that it's actually a Media Bus 2.0 slot by ASUS. Turns out they tried, for a short while, to make their own proprietary slot that combines PCI and ISA. The brown socket is actually just a condensed ISA slot and the cards that fit are usually dual-purpose, combining video and sound or SCSI and sound.
V1.2 and V2.0 Compatiblity
Note that there are two versions and I failed. I went gung-ho and purchased an 'ASUS Media Bus' card on eBay without paying attention to the version. This card was meant to be the ATI Mach 64 + Sound Blaster card and I was really happy... saving slots it a great idea! A week after purchase, whilst the card was still in the mail, I did a little more research and realised that this card would be ASUS Media Bus 1.2, not 2.0! I went back to the seller and found a SCSI + Sound for Media Bus 2.0 and ordered that too.
A few weeks later (thanks to surface mail), a missed-delivery slip appeared in my letterbox and I went to pick up the video+sound card...
Sound? Check! Video? Nope... What? The card I had ordered second arrived first! This can't be good. I still had a V1.2 card in-flight somewhere... would it arrive? I purchased a V1.2 motherboard I saw on eBay anyway; it was cheap and I wanted to use this card... when it arrived!
Anyway, back to this card: It's the PCI-AS300 Adaptec AIC-7880 SCSI + Vibra 16 PnP Sound.
It fits nicely, as one would expect... and works perfectly too!
The V1.2 motherboard then showed up (before the V1.2 card!) and, just to test, I tried to see if the PCI-AS300 would fit...
Nope... millimetres out! I actually think the V1.2 card is lost and I now have a nice and clean Pentium board for another machine... oh wells... Note that the V1.2 slot just says MEDIA whereas the V2.0 says MEDIA BUS 2.0.
I hope others don't make the same mistake!