Problems with MIDI, Sound, Etc.

Question

Hi all,
Well, I have grown up on Macs and my dad has brought home everything from the Plus to the IIci to the Classic Colour when I was a kid 20 years go. Circumstances have forced me to move to PC, and I even had one in my home studio, but I recently had the chance to upgrade and was absolutely thrilled at the prospect of getting back into the Mac world after more than 10 years of absence. So, I got myself a Mac Mini 2.53 GHz (I only upgraded the hard drive to a 500 GB 7200-RPM model, as is common in the audio world), with a Focusrite Saffire 24 Pro DSP Firewire audio interface.
Well, I am saddened to say that so far, I have been BITTERLY disappointed. Problems :
1. This Mac is NOISY!!! I don't mean physical computer/fan/etc. noise. I mean static noise going through the interface. The interface is dead-silent during bootup until, at some point in the sequence (when looking at the Apple logo during bootup), the same static hiss and hum comes back that's been plaguing me for a few days. This noise seems to be matching my activities - it changes when I scroll, when I open a program, etc., for example. So, this is DEFINITELY sub-par;
2. Snow Leopard simply refuses to acknowledge my Roland XV-5050's existence on USB. Ableton Live can find it in its list of "destinations" for MIDI data, but Audio Midi Setup simply refuses to even see it, precluding me from using Roland's very handy Editor. Again, unacceptable, given that I've never had this problem with PCs (although, Roland expressly does not support Vista with the XV-5050 USB drivers);
3. There's something weird about the Mac (could also be Live, I suppose, but I never had this problem on PC) where my music applications do not see the Korg Legacy Cell VSTs that are installed, even though they are in the same folder as, say, Sylenth, which Live DOES see. (And they all end in .vst extensions.) What gives?
I think that's it so far. I've got a very important gig coming up around Christmas time that I have to start getting ready for. I had anticipated virtually zero problems with the Mac, which is why I chose to upgrade, but the reality is definitely otherwise. Please, PLEASE don't make me buy the Dell Studio or something!!
Thanks in advance for all the help!
JS

Answer 1

Korg Legacy and the XV are not critical to my workflow, just items I had invested on I would like to keep. I did not research compatibility with Snow Leopard vwery thoroughly for those two, but I certainly did with the interface, which IS critical. Focusrite has released brand-new drivers that are supposed to be compatible with Snow Leopard, as they loudly trumpet on their web site.
And by and large, they do work - there's just that incessant noise. And THAT's an issue, and somehow I doubt it has to do with the interface as, like I mentioned, the noise only appears during the bootup sequence when, I assume, the Firewire drivers are loaded.
Inputs?