While it stands to reason that the more powerful your computer is, the more benefits you stand to gain with a cable modem, you can use a cable modem with just about any computer system as long as it has a functioning Ethernet card OR USB capability AND meets the minimum system requirements as shown below

  Windows 2000/XP/Vista/7 Macintosh OS X (10.0 or higher)
Disk Drives CD-Rom 3.5" floppy CD-Rom 3.5" floppy
Processor Speed 166MHz or higher Power Macintosh G3 or higher
Operating System Windows 2000 or higher Macintosh OS X (10.0 or higher)
Memory 64 Mb or higher 64 Mb or higher
Required Hard Drive Space 650 MB or higher 800 MB or higher
Video Display 256-color Mac 256-color
Ethernet/USB 10 base T/USB 10 base T Ethernet Card
Additional Software Internet Explorer/Firefox/Chrome Internet Explorer/Safari/Firefox/Chrome