PCI DVR / Capture Cards 101

[RobinBones]

I need to connect 8 to 16 low resolution BNC cameras to a PC to record video using eyeSoft. These cameras have "420 TV lines" of resolution, I'm not sure what that converts to in pixels, I was thinking 320 x 240.

http://www.closeoutcctv.com/ProductDetails.asp?ProductCode=CL-34S&Show=TechSpecs

I looked into "video servers" but they are really expensive compared to the cost of my cameras, and I have a feeling they are over kill when it comes to resolution (unless there are some cheaper versions I don't know about).

I'm looking to PCI cards now, and I just want to make sure that I am not surprised when I get my system setup, and it is only recording 2 frames per second, or something crazy like that.

Questions,

240 Frame rate on a 8 channel card means it will record 30 fps per camera, 240 Frame rate on 16 channel means it will record 15 fps per camera?

Is there is difference in hardware between MPEG4 and H.264 cards?

Will a cheap card from ebay eat more processor cycles on the server than a more expensive one?