intel is the company, pentium is a line, just like you are on AMD (the company) on an athlon chip (the line)
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Some applications won't work on 64 bit operating systems, but they are few and far between, the only ones i have found so far are very old computer games and some office software, like my old schools VPN software didn't have the programming to work on 64 bit architecture (the OS uses 64 bit instead of 32 bit architecture of your CPU).
Also, some stuff you have the option to install 64 or 32 bit version, itunes for example is one, the 32 bit won't work on 64 bit OS and vice versa, so if you ever download software, see if it has the option, if it doesn't chances are it is compatable with both
