Can a 64bit Citrix server running a 32bit app through WoW64 handle just as many instances/users as the 32bit Citrix server equivalent?
And if so if I up the memory in the 64bit server will the number of instances/users scale too?
Or are there some strange memory considerations with a 64bit server running a 32bit app?
Just as an example - We're currently piloting running a 32-bit app on 64-bit.
Increasing memory on the server to around 12G (from 4), allows us to run around 130 instances of the app comfortably. On 32-bit, it's more like forty instances.
Of course, Your mileage may vary.
There may be other concerns to interest you though, especially printer drivers, depending on what solution you use there.
The constraints for a 32 bit Citrix (or Terminal) server are usually in the kernel resources: paged pool, non paged pool, session view space and system page table. On 64 bit OS this is no longer a limit so yes you could run more instances/users. At some point other resources like cpu and disk i/o will become a bottleneck of course.