was wondering if 32 bit XP Pro will run on a 64 bit system

The majority of systems running XP pro are most likely 64-bit. Only some extremely expensive chips can't run 32-bit applications, since they are native 64-bit unlike desktop chips.

No. You will need a version of Unix.

But it will run on a 32 bit processor with 64 bit extensions... Which is what intel and amd mostly produce.

If you have a true 64-bit system I envy your job as a CEO or politician

It's just an old Sun One with a Sparc IIi. Nothing to be envious of. Went EOL a year or two ago, so went AWOL in my boot when it was replaced. I'd rather have one of the new Niagara 2's, but can't justify 14K USD.

Well, if you were a CEO or politician I'm sure 14k would be easilty justifiable.

NO if you are talking about RISC systems. (Sun, SGI, etc)
YES if you are talking about x64 based systems (Athlon, C2D, etc)
I hope someone can explain the difference between a CPU with "64 bit extensions" and a TRUE 64 bit CPU (more abstract than RISC vs. CISC). THANKS!

Yes.
Any XP 32 bit will...and also 32 bit XP will use alot less RAM and run things faster than Vista as well as never have'n program driver issues of any of the MS 64 bit OS's even XP 64 bit.

Most XP OS are 64 bit?
I don't think so and doubt you can show thats even close to real life.

All programs written for 32 bit XP run....but they do not all run on 64 bit XP even after all these years of supporters of XP 64 bit trying to get the rest of the world "up to speed".

The point is that 64 bit OS for gamers/home/small office is still a joke that developers are not finding funny or bothering to waste development money on....still.

@ this point in time 64 bit OS for -most of the earth- is about the same as Vista owners....next to nothing.

ty for info it will be running a intel E8400 45nm cpu. on a gigabyte p35 mobo. So i was worried that my os wouldn't run on it. But from what all of u say i don't necessarily need to upgrade. ty for all help

OK, I'll try for a fairly simple explanation...

A 64 bit CPU has the capability of 64^2 instructions. Obviously, far more instructions than any processor needs, hence the 'reduced instruction set'. Its obvious advantage lies in the flat memory model that a 64 bit memory model allows. A 'complex instruction set' CPU is still limited to a 32 bit instruction set, but with 64 bit extensions that require more CPU cycles to execute - essentially two complete CPU cycles to do what would only take one CPU cycle on the RISC processor. Also, the x86 - 64 CPU will require a 32 bit memory model, plus a 32 bit offset to achieve 64 bit memory access, obviously not a flat memory model. There are differences between various RISC processors, but I said 'fairly simple'.

No, no you misunderstood me. What I mean is that most systems run XP pro (32-bit) are x86-64 machines. So yes, to the average Joe, 32-bit XP Pro will run on a "64-bit" system. Sorry for not being clear.

Yup, every processor since P4 is 64bit. No need to worry, they run a 32bit version of windows just fine.

ZOldDude, you never cease to amaze me with your FUD. So what your saying is that Linux is HORRIBLE because it gobbles up 100% of RAM available? What you WANT is an operating system to use ALL of the RAM, not some of it. It's there, might as well use it!!

Agreed, I'd rather XP load Crysis into my RAM while I'm on the net so it starts up straight away, but nooooo, I have to wait for it to load up entirely every single time. At least Vista loads up some of it already, although not all of it.