I don't know much about 32 bit and 64 bit. I had been using 32 bit and it's crashed (not working properly and i don't know how to recover) question here..... and i don't have backup and i run on 3.2 dual core intel processor can you recommend me which would be better, and i do web development(php and mysql) and learning python.
There are no big performance differences between 64 bit and 32 bit in Ubuntu. I tried both for years now. Let me point to the actual PROS and CONS for the 64 bit since you have been in the 32 bit already:
64 bit PROS:
Support for more than 4 GB RAM (without any kernel modifications, 32 bit PAE support, etc..) The sucker supports more than 1 TB.
Gives performance boosts ONLY if you are doing some very intense work that needs more than 4 GB Ram. Am not talking about playing, watching videos or listening to music. Am talking about server with a million users, rendering shrek 7 christmas edition or something very big like making a 3D version of the galaxy.... from scratch.
64 bit CONS:
In the past (2012 or less) a whole bunch of programs had issues. For example flash (even the 64 bit version) had some glitches and more. If you thought you had issues with 32 Bit on those times, changing to 64 bit increased your chances of having more. For me it was a nightmare on PC street. This obviously changed and it changed very quickly. Since 13.04 I would say, 64 bit got much more stable, easier to work with and it was very hard to get a 64 bit problem. On 13.10 I did not have any issues whatsoever. Now on 14.04 it is more recommend than ever before to move to 64 bit but only if you have the following hardware:
Recommended for the average user that has 4 GB or RAM or more and hardware that supports 64 bit architecture.
There are many issues still in the 32 bit that will get even bigger in the 64 bit one. Apart from that 64 bit is still very new (Even if it came out around 2000) but the majority of the programs made (Even today) are mostly for 32 bit.. Nowadays, 64 bit is the best move. When I wrote this answer it was January 2011. We are now in April 2014 and I can really say that 64 bit is much better than 32 bit in terms of performance, stability and more. Of course, the need for a program to use even close to 4 GB is not yet a big problem and the real need to use more than that applies to intense apps.Test out 32 bit if you want but if you have a computer with enough RAM, CPU and a good motherboard (From 2005+) then I would really recommend 64 bit for you.
Hope to have helped.
If you dont have any specific reasons for installing 32 Bit then you should go with 64 Bit. At the following URL you can find the performance comparison of 32 Bit and 64 bit linux versions.
http://www.tuxradar.com/content/ubuntu-904-32-bit-vs-64-bit-benchmarks
You can see that 64 Bit is faster in many places. You can also have more than 4GB ram in 64 Bit but not in 32 bit. Also there is ubuntu community help page here and they also suggest installing 64 bit.
I am running Ubuntu Lucid 64 Bit on my machine and I dont have any problems. All applications that I need are in the repos and everything works. Back in 2009 I tried 64 Bit version of Intrepid but reverted back to 32 Bit because many softwares didnt have 64 Bit versions then but that is not the case now.
If you have more than 4 GB of RAM go for 64 bit else 32 bit is just fine.
As for this question: If you plan to re-install your operating system completely, choose the 32 bit version. There's really no need for you to try 64 bit.
But it's really not that important. Ask another question here about how to best do that re-installation, keeping your data. Make sure to explain your situation in detail, what hardware you have available (hard disks, usb sticks, cd drives, ..), how your hard drive is partitioned and so on. If you need help figuring all of this out,you can join the Chat room or search the site.
Your problem is quite a difficult one. But we'll help you as best we can.
I find it quite amusing that the usage of 64bit is so closely bound to memory in the machine. 64bit means as well that per processor cycle you are able to process twice the amount of data comparing to a 32bit operating system.
Use 64bit in case you do
I am doing a podcast and using 64bit with my notebook saves a lot of time when doing audio processing (noise reduction, normalizing, compression, ...). My notebook only has 2 GB of RAM.
I've been running 64-bit Kubuntu for years without an issue. I think that any objections to 64-bit are just FUD and you can ignore them.
One relatively new reason to use 64-bit: if you are interested in virtualization, Docker does not run on 32-bit kernels (as far as I know).