[plug] [OT] pc builting confusion

[Craig Ringer]

On Tue, 2005-03-22 at 18:12 +0800, Ryan Smith wrote:
> hello
> 
> I am trying to built a computer for a friend.
> He wants it to last for a while (about 10 years). From this we came to
> the problem of, how long will software for a 32bit cpu be developed? Or
> are 64bit cpu's going to take over soon?

I wouldn't be surprised to see 64 bit CPUs become fully mainstream in
the next year or two. Before support for 32-bit only CPUs even begins to
flag, you'd need:
  - All the "current" 32bit systems to age to "obsolete" (min 3-4 years)
  - Microsoft to release a new version of Windows for 64 bit computers
    that sees near-universal adoption

As for the vast majority of software there's no serious difference
between 32 and 64 bit CPUs, and as the "consumer" 64 bit CPUs are all
compatible with 32bit software for their architecture, I doubt software
vendors will stop making 32bit compatible software for a LONG time.

I suppose there's the memory cap to consider, but that'll only hit
scientific software, games, and a few other areas. Not even Mozilla,
OpenOffice and Evolution can (quite) use up 4GB of RAM :-P 

In summary, I wouldn't worry too much.

> Also what is the difference between socket 754 and socket 939 athlon 64?

Different processor support. Socket 754 is being phased out ; it's the
older Athlon 64 socket. Socket 939 is the new socket for Opteron and
Athlon 64. I think there are some differences in RAM support etc too,
not sure.

If you're thinking in terms of upgrading, I'd advise you not to bother.
It's rarely (not never, but rarely) worth upgrading the CPU in a system
- you'll usually want to do the CPU, motherboard, and RAM at the same
time. So really, who cares what the socket is from an upgrading PoV.

> What are peoples thought on this. Should we go for a cheaper 32bit cpu
> or a 64bit one?

I'd say it's much of a muchness. That said, the Athlon 64 CPUs aren't
actually all that much more expensive when you consider the total system
price - and if your friend is thinking in the long term, they should be
prepared to spend a little more now to get a system that'll last better.

That probably applies to things like fast RAM support, SATA, etc too.

-- 
Craig Ringer