Can we run WLS 32-bit with a 64-bit JDK?
We do not recommend this because when you install WLS in 32-bit mode, 64-bit native libraries are not installed. Also, the scripts installed during 32-bit mode WLS installation will default and point to 32-bit libraries. This applies the other way around as well to WLS 64-bit installation using a 32-bit JDK.
What is the performance impact and memory requirement differences between WLS 32-bit and 64-bit?
This depends on what the application requirements are. If you need a large heap size, then 64-bit WLS is probably the right option. With smaller heaps, 64-bit WLS running with 64-bit JVMs are likely to run somewhat slower (certainly don’t expect them to be faster) than 32-bit JVMs, but it may not be very noticeable depending on the application.