When you're syncing devices, console automation, lighting, triggering synths, etc., there is definately a hearable quality change in MIDI timing. Tighter triggering compared to audio at given latencies, it definately changes. You do have to be able to know what to listen for. Some boards do it better than others, and sometimes they have the same processors and chipsets...one will just be better across the board. If its reproducable, thats what we go with.
I use an Intel P35 board in my own studio system. It works great for me, and I highly recommend it to almost anyone. If I was using a PCIe expansion chassis for a HD system, or for lots of UAD cards I'd personally want the X38 because when I tested it, they worked more consistantly on it. Audio systems are very finniky, especially when you are adding more and more PCI cards, as more people are doing these days, at least our clients.
Here's a good specific example of something I found in testing. When using a combination of UADs and MADI cards (all slots full on any given board), they will often totally change performance depending on which slots they are installed in. Sometimes the UAD in the wrong slot will cause the system to completely not post at all. Sometimes the card will load to a lower percentage before it starts having sound issues. One of the things I liked about the Intel X38 is that it performed more consistant moving the cards around to any slots.
Benchmarking sites, gamer info, super geek nerd talk, none of it matters to me. When I put components together and it sounds good, and works consistantly..THAT matters.
