Hello Cheekykid!
Well straight away there is the possibility of overclocking that older chip up to 3.0GHz maybe 3.2GHz? . . . maybe even swapping out that DualCore for a used QuadCore (£80 ish) and overclocking that up to 3.0GHz . . . 2GB of DDR2 isn't loads but depending on your memory requirements it may suffice for the moment!
Ok well it seems somebody has been reading a PC magazine or had a quick scan of the forums to see what the latest "Buzz" is?

. . . forget this "top of the line" business as pretty much all the hardware out now is amazing . . . top of the line stuff is a concept made by the marketing men to rob you of your cash! ££
Also, I'm not sure why somebody who owns an nVidia 8800 XYZ and who "rarely play games" is looking for a new GPU?
What is the make and model number of the PSU please?
Ok I know what is "movie encoding" but what do you mean when you say "I mainly do multitasking"
No I don't . . . I think you may be about to *burn" £900+ that you don't actually need to!
Here is a spec for you costing £580 . . .
this leaves you £920 of your money to spend on something else than computer hardware . . . this gives you a nice HexCore processor inc 3rd party HSF to keep it cool, 8GB of fast DDR3, a modern SATA 6Gb/s & USB3.0 motherboard featuring built-in graphics (IGP), a fast SATA 6Gb/s 64GB SSD and a nice 1TB HDD for storing your videos! . . . if your rarely game you can either keep you older nVidia Geforce 8800 or sell it and use the motherboards IGP
[/QUOTE]
Multitasking= Photoshop/encoding/maya
My PSU is 620W Nesteq semi fanless/no longer in trade. As for my mobo its an asus P5W DH deluxe which i dont think it supports a quad core.
My concern is quietness and quickness. I kinda feel my pc being not as fast as it used to even if formated. Is the 980x really a waste of money? reviews do suggest its quite a beast.