I have no idea what Edius is so I'm not going to be of any help on that. Perhaps someone on these forums is familiar with it and can provide some information. You also might want to check with the manufacturer and see if they can provide some information.
As far a running MS Windoze on your iMac there are 2 ways you can do it. You can use Boot Camp which comes with OS X on every new Mac. This allows you to boot in either Windoze (XP, Vista or Win 7) OR in OS X. When you use Windoze this way your Mac essentially is a PC and operates identically as any similarly spec'd PC would. There are numerous web sites where you can find installation videos and tutorials on Boot Camp, simply Google 'Boot Camp Tutorial' and you will find many.
The second way of running Windoze is using virtualization software like Parallels or VM Ware Fusion. Both applications do the same thing and one isn't 'better' than the other. The advantage of virtualization software is you can run Windoze and OS X simultaneously. With the current line of Macs you probably won't see any performance degradation unless you are playing Windoze games or doing 3D renderings. I happen to use Fusion and have for 3 years, the first thing I noticed was how much faster Windoze XP loaded compared to my old PC. My needs are different than yours of course and I now rarely use Windoze but I have noticed as with my old PC the longer it's installed on my computer the slower it becomes. The good news is OS X performs as well as it did the first day I got it.
NOTE: As with any PC if you decide to run Windoze on it that partition is susceptible to any and all maladies and virus's that any Windoze box is so take care to protect it. Worst case scenario is if the Windoze partition does become diseased this will in no way affect the OS X partition.
Roger