I have just installed Fedora Core 5 64bit linux in my system. I like it, but there is some problems associated with its being 64 bit.
Macromedia(now Adobe) have not released a Flash plugin for 64 bit Firefox. This is in most cases a good thing - as I won't have to watch annoying flash ads. But it is a problem when I am trying to view videos in YouTube or Google Video. Also, Google Analytics is impossible to use without Flash. There are some solutions like using a 32 bit firefox on a 64 bit linux - but I like it better if there is native support. For automated installation see Howto Install 32 bit Firefox with Flash w/sound and Java for AMD64.
Not much of an performance boost in Desktop systems
64-bit binaries are not twice as fast, either. You are unlikely to notice any discernible speed difference, particularly with desktop apps.
What you should (and shouldn't) expect from 64-bit Linux - A must read if you are torn between choosing a 64bit and 32bit OS for your system.
Can't get IE to work
As I have promised in the 'Installing Internet Explorer in Linux' post, I have installed IE using Wine in the system. I did this in a FC3 system(at work) and a FC5 system(at Home). IE works perfectly(or close enough) on the FC3 system - but fails miserably on the FC5 system. I think this is an issue with Wine. I had to hack it a bit to work with my 64 bit system.
Another problem I have noticed is that the system, on the whole, seems a bit slower than FC3. I have seen other complaints like this on the net - but very few valid solutions.
I am trying to speed thing up a bit by disabling unwanted services. But still I think that the FC3 was faster. I am going to upgrade my RAM to 1GB from the current 512 MB - maybe that will solve the problem.
If nothing works, I will install a 32 bit version of FC5. I will have to re-configure everything - but I need speed.