32 bit os vs 64 bit processors

[shane_hudson]

if you have a 64 bit system and a 32 bit os does it effect the performance of the pc. will a 64 bit os perforrm better with a 64bit processor or will a 32 bit os perform better because there is les processing?

[Dwarf]

Hi Shane,

A 64-bit capable system can run both 32-bit and 64-bit versions of an operating system without difficulty, however when running a 32-bit OS you can have memory limitations since such a system can only address a maximum of 4GB (this includes physical RAM and the address space used by other hardware devices). Please note that I am only referring to Microsoft Windows here (possibly with the exception of 'Server' versions) and that other OSs may or may not have this limitation. The 64-bit version of Vista (and XP) does not have this limitation, but you may have driver issues as not all hardware manufacturers have got 64-bit support for their devices (although this situation is improving). As regards performance, generally speaking there is no difference between the performance of a 32-bit OS on a 32-bit processor compared to the same OS on a 64-bit processor - both processors are equally capable in this respect. There might be slight differences in performance though between the 64-bit and 32-bit versions running on a 64-bit processor, but this is down to the difference in code between the two versions. It should be noted that this does not mean that a 64-bit system is always faster than the equivalent 32-bit as it depends on hardware support and how efficiently the code has been written (I remember writing machine-code for the 6510 processor as used in the Commodore 64 back in the 1980s and then rewriting the same code to make it more efficient, sometimes by a factor of 3-4 times). It also depends on the program(s) running as some are more capable of utilising 64-bit than others.

[megachirops]

I agree with the previous post that for most purposes the main difference between a 64 bit and a 32 bit OS is in the amount of memory you can address.

For numeric and floating point computation, however, 64 bit programs can have a large advantage - on C and C++ numeric-intensive programs that I have written, I get almost twice the speed with the 64 bit compiler and running on the 64 bit OS. (by the way - I find that a 32 bit program runs at the same speed in the 32 and 64 bit OS, so it is the 64 bit compilation that gives the speed advantage).

[shane_hudson]

Both replies helped alot. Thank You. I have Vista Home Premium 32 bit loaded on my System. I have the ASUS M3A, AMD Phenom 9850 Black edition, 4GBs of OCZ's PC 8500 Reaper series memory and the Geforce 9600 gt video card By BFG. Pretty sweet system I think but I want to know if my system would be more efficient with the 64 bit os?