Windows 7 - Identifying Media Center performance bottlenecks : a discussion?

My HTPC has just expired, typically not long before Christmas when I've got no money and I really want to make use of it (the money & the machine!).

So here I am mulling over in my mind what to replace with - currently it is an AMD 4850e in a Gigabyte boards - my Win 7 OEM license requires me to stick with the nearest possible, whilst an i3 machine would be nice - it's not for games but with 45,000 music tracks the current machine does grind a bit and having welly to spare / expansion options would be nice, or something like an E-350 - seems to fit the bill for Media Center?

The E-350 seems like a good option actually but I'm concerned about performance - I understand it will do HD video no problem but on the raw processing power it's really not much above a calculator and there are times when Media Centre does seem very slow.

So, turning on my i7 machine and starting up MCE I sat there looking at where the bottlenecks are - going to Album Artists appears to take an age to populate and I rather like that view (more rows on the page please microsoft, we've got big TVs nowadays!).

What did I find? Well, interestingly my first try today I was getting low page faults, low disk usage, low processor usage.

On my second try (after a reboot) the traffic is all against Media Player database on disk.

So I'm left wondering what people's opinions are on the best way to improve Media Center general performance - does it need CPU / RAM / disk?

Why did the machine have a first go where it seem really slow to do anything but didn't seem to be maxing out any components? I'm presuming that for some reason it had decided to update/ rebuild the Media Player database - is there a way to make that only happen on demand as it is rather frustrating - and if it was that why is that rebuild so slow and not taxing on an idle machine.