ODM3 does not demand particularly high-spec hardware, running on virtually any machine from 1GHz upwards.
ODM3 performance will depend on the intended volume of data - projects with a large number of wells (>100) will, like any other Windows applications, benefit from more memory and faster processors.
Typical specifications would be:
Operating system Windows 2000/XP
Processor 2.0GHz+ processor
Graphics Anything reasonable with 16 bit colour or better
Memory 512Mb and greater
Disk we budget 3Mb/well but obviously depends on the number of logs