WebLogic 6.0 SP2, Solaris versus Windows NT/2000 (HotSpot JVM)

[Steve Feldman]

Fellow Developers/Administrators,
I have an unusual performance issue that baffles the mind. I have been running a simple (4) node WebLogic 6.0SP2 cluster on Windows NT for the past 8 months. I am using the JDK 1.3.0 (HotSpot Client). I've tuned my cluster to extreme lengths and it runs very efficiently. I've got a (4) CPU (900+MHz P3) with (4) GB of RAM.
Recently, I was requested to move the cluster from NT to Sun. No problem...I ported everything over, made some minor tuning adjustments and wahlah...I had a (4) node WebLogic cluster on Sun. (4) CPU (900 MHz Sparc III) with (4) GB of RAM
Well, since moving the identical cluster application from NT to SUN, I have seen considerable performance issues. I understand that the hardware is different, but tasks that normally take 10s on NT (pulling medium to large data sets from Oracle) are now taking up to 4 minutes in my Sun environment.
Has anyone seen anything like this before? Do you know of anyway to overcome this issue?