I am a total newbie to Linux.
I plan on installing FC4 as a single OS (no WIndoze) on a Dell Precision 670 with

2.8 GHz Xeon processor with 64EMT
1 GB memory
Nvidia graphics card
160 GB hard drive

I will be using the computer for molecular modeling studies (lots of computations and graphics), mostly using open source software. In addition, I will use Firefox, OpenOffice, etc. for web and document use.

The question is:

The processor is a 64-bit processor, and one can install the 64-bit version of FC4. However, there does not appear to be a lot of software out there at present that is true 64-bit. I believe that the 64-bit processor/OS are backward compatible, and can run 32-bit software that I plan on installing. Is there any downside to installing the 64-bit FC4 and using both 32-bit and 64-bit software (obviously using th 64-bit version when available)? Is there anything special that needs to be done under these circumstances?

Since most software is still 32-bit, would it be possible/better to install the 32-bit version of FC4 and only run 32-bit software? I'm not a total speed freak, and am not worried about a potential (albeit small) decrement in performance/speed.

Thanks in advance.

If you want ease of use, I think you'd be best off sticking with 32-bit FC4. Not very adventurous, but there is a lot more stuff available pre-packaged for it. I'm not sure how easy it is to run 32-bit versions of programs in the 64-bit version of the OS, but it's bound to be more complicated than just running everything 32-bit.