I HAD a Delta33 on a VIA Pro133a motherboard (Celeron500) - after weeks and weeks of system tweaks, calls to tech support, etc. I finally got my system to record without pops/clicks/skipping. Then something changed about a week later (not sure what??) and I was never again able to get my system to record properly.
The M-Audio folks told me to get a new motherboard 'cause they have had all kinds of problems with VIA chipsets and their cards. Kind of ridiculous, I think, that they don't put some type of disclaimer on the box or something to let you know of these incompatability issues.
Anyhow - I ended up getting a new motherboard (with an Intel chipset) just last week - havent' been able to set up my system yet though. My own opinion is that I wouldn't advise the Delta 66 with a VIA chipset unless you want to be frustrated. But I know that there are plenty of other people (some that post around here) that have had no problems....