32 bits or 64 bits O.S (in a 64bits CPU)?

What are the advantages/disadvantages of using one over another (in a 64bits CPU),for someone that uses the computer for:
- browsing the web
- see movies and listen to music
- occasionally use of office software, pdf reader...

Assume 4GB of RAM, and a Linux distro as O.S.

When i google for the subject i find people saying that for the average home user, 32bits is the better choice because of compatibility,
and because the gain in processing speed by using a 64bits OS will be unnoticeable for that kind of user; in the other hand i see all kind off benchmarks showing that
64 bits O.S is faster...

so using 64bits offers any advantage for the kind of user mentioned? Will the use of 32bits O.S generate less heat because it uses less of the 64bits CPU resources? Also why 64bits distros have higher system requirements?

Considering that most distros offer 32bits and x64bits versions, what are yours thoughts? Thanks!

 

There is NO performance difference from 32bit to 64bit CPU in general.

x64 architecture has more registers and other efficiency improvements (eg memory access) over x86.

You will only see performance if you are CPU bound, video is a good example of where you could get approx 20% more performance from x64 processors due to the extra SIMD instructions and registers on the chip.

CPU can be more power efficient under x64 due to not needing to at full speed as much (but I suspect the difference in real world will be marginal). I don't think CPU can selectively power off specific parts to save power ?

I've run 64bit for years, don't really get compatibility issues in distros in generally due the all the code being compiled in the same way for each variant of a particular distro in general.

Cheers, Nick

 

Thanks for your answer Nick. It does seem that the option for a x64 OS when using a x64 CPU is in fact the better one. One other thing to consider is that with x64 OS, more memory can be used for cache, what will improve the performance. Also, in my particular case, my laptop uses shared video memory, so the more memory can be accessed, the better, i guess.

 

64bit has access to more registers. Stack register is nice, and only on 64bit.

64bit addresses more data, including RAM or disk usage.

64bit has a larger address space, which makes ASLR more effective.

I'd just use 64bit.

 

While there is some truth to this, I have found few things I wanted to use incompatible. For example my printer drivers used 32-bit code, fortunately gutenprint very quickly added support for my printer so the manufacture provided drivers are no longer needed. If I really needed to use a 32-bit program I could add 32-bit support. So far I have not needed to do this. Also it shouldn't be a compatibility problem for most x64 distributions since they include 32-bit libraries so both 64-bit and 32-bit programs will for the most part run just fine. My distribution of choice is pure 64-bit, 32-bit programs with not run without adding 32-bit libraries to the mix. Only 32-bit program I have installed is Skype, it was statically compiled with the needed 32-bit libraries. This is an older version of Skype (4.0.0. in which a static tarball was available. The current version (4.1.0.20) is available only in a dynamic tarball. I may have to breakdown and add multilib support if I need to upgrade.

I don't see any major advantage using 64-bit for the the kind of user you mention. I have both 32-bit installs and 64-bit installs of my preferred distribution, usage wise I see no advantage in 64-bit over 32-bit. I simply choose to install a 64-bit OS on a 64-bit capable machine, if it's not then I will go with 32-bit.

I don't see much difference in heat produced. Where I live that is a constant issue. It' really matters not if the machine is 32-bit or 64-bit. The heat factor still feels about the same.

I would say that some 64-bit distribution have higher requirements simple because lower spec systems are generally not 64-bit. You not going to run x64 on an i686 system.

 

You might be interested in the recent performance comparison test on Phoronix.

 

Thanks.