I have been thinking about buying a new mac for video editing that I will be starting very soon.

I current have a 2008 model Macbook pro, which I am trying to run Final cut pro x and After effects on but I am getting very slow rendering and exporting, especially with After effect. I cant even play back some clip without it slowing down to 2fps. So this is a fairly annoying problem.

I have been looking at some different macs and spec.

I was thinking of getting the 27" imac with these specs

3.4GHz Quad-Core Intel Core i7
16GB 1333MHz DDR3 SDRAM - 4x4GB
1TB Serial ATA Drive
AMD Radeon HD 6970M 1GB GDDR5

Not sure whether this is the right choice,
any other information would be very helpful thank you!