What is 64 bit, what's it do better?

XP is 32 bit as I understand it. But Vista is 64 bit. What specifically will 64 bit OS do for us? Is it more for the future or will we see advantages right now if running a core 2 duo with Vista? What advantages does it offer?

 

Vista will actually come as 32-bit and 64-bit versions. The 64-bit version though can support more memory and can run a bit faster on a 64-bit processor than the 32-bit version. Keep in mind that 64-bit drivers are still scarce. There are still companies that have not written 64-bit drivers for their hardware.

 

So 64-bit is really nothing that is going to improve performance until the whole market designs stuff to accomodate it right?

Vista on a core 2 Duo right now will likely run in 32-bit?

 

Right now it offers no performance advantage, little software development has been done in 64-bit, and a software program would have to be written optimized for 64-bit instruction processing for there to be an advantage. In 3-years time you may see more advantages in having a 64-bit processor.

 

We do have 64bit XP, and we will have 32bit Vista early next year. The biggest difference is the ability to address more memory. 32bit addressing results in a cap of 4GB of RAM, while 64bit allows for a cap of a ga-jillion. As well, some say that 64bit registers means your CPU can work with twice as fast because you're accessing twice the amount of data as 32bit registers and we all know memory access is the bottleneck to any streamlined chip set. I had high hopes that Vista would take the leap to 64bit and say "32bit be damned!!!" or "Ok here's some crappy emulation software for you..." but it's not the case. 32bit looks to dominate for years to come, due to both lack of consumer and third party support. Commercial uses for 64bit systems are thriving though.

 

Hmm, so there is no advantages to 32 bit except, there are actually a couple of disadvantages, such as lack of program hardware support. Or can 64 bit xp, run 32 bit xp programs?

 

Well they did it with DOS on XP so why not...

 

Just think about those years from 16bits to 32bits. 64bits will have the same path although the duration will be much shorter.

I will say 64 bit arch will mostly speed up multimedia production and 3D apps. The throughput will be doubled for content heavy process. The regular Office typing still won't get much from it.

 

Nope, that's not the same. The CPU's registers are able to hold 64-bit values, yes, but that doesn't make them twice as fast. It simply means it can operate on bigger numbers. (And has nothing to do with memory bandwidth usage)
Previously, a register could hold up to 4.2 billion, roughly. So if you wanted to add bigger numbers than that, you'd have to split them up, causing an extra slowdown. But almost all everyday operations fit fine within 32-bit registers, so there's no speedup to be achieved there. One register can still only hold one number. So the "64-bit-ness" itself only provides advantages in the following situations:
- Scientific simulations that require very high precision and awfully big numbers
- Addressing more than 4GB RAM.

Those two improvements are due to the 64-bit support itself.

There are a few other advantages and improvements to 64-bit. Basically, when AMD came up with the 64-bit extensions to their CPU's, they took the opportunity to also add a handful other fixes and tweaks which can provide some speedup even when you don't need the above. (For the technically minded, it doubles the number of registers, provides more efficient stack operations and a few other things). These things have the potential to offer *some* speedup even for "normal" applications. (think 10% or so, depending on the application)

Next question, yes, a 64-bit OS can run 32-bit software with no problems. It can't run 16-bit though, which basically means DOS-apps won't work. (At least without Dosbox or similar emulation)