I don't believe that there is a 9.8 Workgroup Edition. 9.8 is a special release for PureScale, which requires a license for Enterprise Edition. Eventually IBM plans to fold PureScale into the same existing releases used by the other editions, and will be a extra cost Feature code on top of ESE, but for now 9.8 is PureScale/ESE only.
Regarding hardware requirements for Workgroup Edition, they are pretty minimal, but for best performance you want as much memory as you can afford, especially since you don't pay for DB2 based on the amount of memory you have, and memory is a key performance factor. CPU is a little more tricky, since it depends on what your licensing is based on (CPU sockets, PVU's, or Authorized Users) as to how many CPU cores you will want. Also, keep in mind that DB2 Workgroup Edition 9.7 that is licensed for PVU's or Authorized Users can be installed on a server with a maximum 480 PVU rating. If you license by CPU sockets, you can go as high as 960 PVU in certain configurations.
Here is a link to determine PVU's:
This article discusses different licensing options for DB2 9.7 (although you may need more details):
Last edited by Marcus_A; 11-27-10 at 00:55.
M. A. Feldman
IBM Certified DBA on DB2 for Linux, UNIX, and Windows
IBM Certified DBA on DB2 for z/OS and OS/390