Capturing HD from Xbox 360

[.TheCriMson[K20]]

I currently have an external capture device that i run my original 360 cables out to; along with my tv. My question is, i want to capture the true HD gameplay. I would prefer a capture card that accepts HDMI input and has an output to tv also, so i can view it on both devices, but i cant seem to find one anywhere. Anyone know of anything like this?

Also, any idea on what type of specs my computer would need? I'm currently building a new desktop, and want to run an e6600- overclocked, 2-4GB of ram and mad amounts of HD space. Ive just never worked with any type of HD video editing and capturing so im not sure what kind of cpu utilization it uses.