2 node dell poweredge 59nn with md3000 das storage - 64 bit windows,cisco switch for interconnect, UDP 1GB storage raid 5 on das with 7 disks semi spatial application for land management widows .NET Application using IIS as web server - PL/SQL calls to D/B THRU 10.1 CLIENT Database 10.2.0.1 I sent a post earlier about 32-bit windows ,how when both nodes ran performance was poor, stop a node and performance is good.Well i have upgraded to 64-Bit and the same things happens. When I run a j2ee application against same database it performs well. I have fixed hosts files and tried changing the datasource on the client to point directly at an instance and also via the load balancer Tns names entry. So far all attempts failed. I know that the application source code is poor, but when it runs on one node it is fine , and that is the vendor response.It is hard to argue against. Tomorrow I will start a thorough analysis, but any heads up will be appreciated.