Not exactly sure what you mean by performance tools.
We have used products from Centerfieldtechnology. They help a lot to find offending SQL statements, and where the performance problems really are. It has saved us a few times. PC Client, with the engine running on the AS/400.
Dan Doenges
Dept 56, Inc.
OW 7321, SP 12.5, coexistant, ES 400 V4R5, DS NT