Holy crap - Have I become an eGO celebrity?
Chemically - I just read your message today (saturday) as I had a 4 hour drive home from college due to it being the weekend I am celebrating my birthday.
I realised how long this was so I moved the conclusion here - to the top - so that people can see what I said and skip the explination if they want. What I think you shoudl do is buy nothing - Or upgrade to Vista 64 (home premium or Ultimate if you can afford it). It is true that most games are written only in 32bits, however there are programs and soon games that will take advantage of the 64bits. Last time I heard the unreal serries was looking forward to using 64bits.
So, as long as you are happy with your XP and your RAM then dont bother paying for the same operating system twice. But if you want to be able to take advantage of your processor the way it was meant (even only with 64bit internet explorer lol) then get Vista 64 and hope that they start patchign games or making the new ones 64. Tons of software is 64bit but mostly linux server stuff and super computers.
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Weather it be Vista or XP or Linux etc, the only difference between a 32bit OS vs it's 64bit counterpart is how long a hardware instruction is. For example: one instruction might say "add $r5, $r6, 999" which might mean - add the value in register 6 to the number 999 and store the result in register 5.
In a 32bit processor it accepts commands / instructions that are 32 bits wide. The add example instruction I gave above was 12 charactors long (not counting commas or spaces) - however, when it is converted to Binary by the compiler it will be 32 bit (1's or 0's) long.
In a 64bit processor the instructions are 64 bits long, which means there is a possability to have more or more complex instructions, instructions that perform many actions, or simply the same instructions that can accept larger numbers. Perhaps now I can say "add $r5, $r6, 999999999999999"
With a 32bit processor you can only have 4 GB of RAM that can be communicated to by the processor. The reason for this is because 4 GB = 4096 MB = 4194304 KB = 4294967296 Bytes. In binary the number 4294967296 is 32 bits long.
With a 64bit processor you can infact put ALOT more RAM in your computer - aproximately 16 EB (ExaBytes).
XP started off as 32bit only, and AMD began making hybrid chips, they run in both 64 and 32bit modes. Then XP got an upgrade to 64bit and Vista comes in both. Linux distros also come in both varieties. Mac tries hard with their 64bit extentions but the g5 is not true 64. hah Mac. I dont know if they have anything newer in that dept.
If you are using a 32bit OS then your processor and apps are in 32bit mode. Period. If you are running a 64bit OS then your processor is in 64bit mode and your applications can be either 32bit or 64bit. Those running in 32bit just get a whole bunch of zero's (32 to be exact) added to each instruction.
An interesting topic never talked about is that although 64bit instructions could do more, and talk to more RAM (which is faster than your hard drive by many factors of 10) thus allowing programs the ability to talk to enormous ammounts of RAM, passing a 64bit instruction takes longer than passing a 32bit one. Hardware designers have lots of nifty tricks and I am learning about some in my processor design class - but it always beggs the question - is the increase in front bus requirements more or less than the gain from 64bit instructions? Obviously 64bit is better lol.
se begining for conclusions.