32bit and 64 bit

[Luigi Manto]

Hi Everyone! Here's my question. In a performance point of view, will there be any performance degradation if your going to run a 32bit application on a 64bit environment? How about running a 64bit app on a 32bit environment (Is it possible)?

Thank you in advance!

[Michael Tully · Accepted solution]

Hi,

You should see performance gains in going to a
64 bit platform providing it is capable of doing so.

See this table:
http://devresource.hp.com/STK/serversupport.html

No you can't run a 64 bit application on a 32 bit system. You run 32 bit applications on a 64 bit system without any problems.

Cheers
~Michael~

[Ravi_8]

Hi,

32 bit applications runs well on 64 bit OS(eg: oracle 8.0.5, DB2 5.0/5.2 etc), whereas installing 64 bit appilications (like oracle 9i) on 32 bit OS, by default will get install as 32 bit applications ( oracle 9i on any D-class HP machines will run as 32 bit application even though it is 64 bit application). In some of the appilications like AFS(Andrew file system), there will be 2 different files each for 64 bit and 32 bit OS.

[Olav Baadsvik]

Hi,
You will not see a performance degradation when running a 32-bit
application on a 64-bit machine.
Running a 64-bit application on a 32-bit machine is not possible.

See /usr/share/doc/11dev.ps for good info about porting to 64-bit
It discusses among other things what kind
of applications need/will benefit by
beeing 64-bit applications.

Regards
Olav

[Stefan Farrelly]

Oh yes, there definitely seems to be a performance degradation from running 32bit apps on a 64bit environment. Weve upgraded almost all our servers to 64bit and several apps now clearly run slower (our apps are 32bit). We need to convert our apps to 64bit in order to improve performance. However, the performance degradation is only 5-10% as far as we can observe. So the moral is test your apps thoroughly on 64bit before upgrading production to ensure any performance degradation is not overly noticeable.

No, there is no way you can run 64bit apps ona 32bit server.