2.66 iMac (new, 2009) Vs 2.66 MacBook Pro

Question

I have a quick question with regard to power and performance of the new iMac and MacBook Pro's.
Between the dedicated graphics of the 2.66 MacBook Pro (both 15 and 17-inch) and the 8GB RAM (but shared graphics) of the 2.66 iMac's (both 20 and 24-inch), which would be the more powerful performer? The iMac for it's extra RAM abilities or the MacBook Pro for it's better graphical performance with up to 512 of video RAM?
Many thanks!

Answer 1

But I have not given a estimate for the 4830? The 4850 is 14 XXX
The 4830 is:
Pipelines 640 - unified
Core Speed * 550 MHz
Shader Speed * 550 MHz
Memory Speed *
Memory Bus Width 128 Bit
Memory Type GDDR3, DDR3
Max. Amount of Memory
Shared Memory no
DirectX DirectX 10.1, Shader 4.1
Transistors 826 Million
technology 40 nm
The 4850 is:
Pipelines 800 - unified
Core Speed * 500 MHz
Shader Speed * 500 MHz
Memory Speed * 850 MHz
Memory Bus Width 256 Bit
Memory Type GDDR3
Max. Amount of Memory 1024 MB
Shared Memory no
DirectX DirectX 10.1, Shader 4.1
Transistors 956 Million
technology 55 nm
Features OpenGL 2.0, PCI-E 2.0 x16, Powerplay, DisplayPort support up to 2560x1600, HDMI support up to 1920x1080 (both with 7.1 AC3 Audio), 1x Dual-Link/Single-Link DVI, 1x Single-Link DVI Support.