Difference in performance, if any, in 32 and 64-bit versions of Ubuntu?

Question

I have an Intel Core 2 Duo 2.8 GHz, and as far as I remember I installed the 32-bit version of Ubtuntu 8.04. I have been upgrading since.

I was just wondering if 64-bit Linux provides any performance enhancements? And should I install the 32 or 64-bit version of Ubuntu on my PC from now on?

Answer 1

The only big advantage would be memory. There is a lot of hassle getting a fully running 64-bit GNU/Linux system working the way you want due to compatibility issues with applications and codecs. Phoronix did a test a little while back and there were no significant differences between 32 and 64-bit systems with similar resources. The compatibility hassle in itself would be enough to make me steer clear of the leap, however if you do have more memory, 64-bit Linux can allow each application to use more than the 3G limitation imposed by 32-bit Linux. If you use some of the resource intensive development tools, letting each use more than 3G of RAM may be beneficial. However if you simply want more memory and none of your applications require >3G, you can enable PAE in 32-bit Linux.

Answer 2

From Ubuntu's website, 32-bit and 64-bit differences. Basically what it comes down to is how much memory you will be able to access. With a 32-bit system with 'Physical Address Extension' or PAE, you can hit a maxium of 64 gigabytes of memory that you can access. With a 64-bit system, you will have can have an almost unlimted amount, but most hardware will limit this to one terabyte of memory. When using a 64-bit powered machine, the percived speed of the system is much faster than a 32-bit machine. So from a users standpoint, this is great benefit.

Stright from Ubuntu's website

Unless you have specific reasons to choose 32-bit, we recommend 64-bit.

Whichever you choose, have fun with it!

Answer 3

To add to the above, 64-bit compiled programs actually use more memory:

The main disadvantage of 64-bit architectures is that relative to 32-bit architectures, the same data occupies more space in memory (due to swollen pointers and possibly other types and alignment padding). This increases the memory requirements of a given process and can have implications for efficient processor cache utilization.

So if you don't have above 4GB of ram, don't go 64-bit. You will end up using more of your RAM to run the same programs.

And of course, use the Ubuntu LiveCD for 64-bit/32-bit and try for yourself.

Answer 4

In theory there are some performance benefits to 64-bit in the fact that there are more General Purpose Registers on the chip and an x86-64 implementation explicitly implies SSE2 support in a processor which immediately means that the system can be better optimised than one that is claimed to be x86 compatable (and thus will not necessarily have SSE support).

These benefits are only seen by 64-bit programs though, so YMMV.

See http://en.wikipedia.org/wiki/X86-64