What are the benefits of 64 bit CPU?

[nirdinur]

I read lots of stuff about how 64 bits is usefull/useless, good investment/waste of money. I am really confused by now. So lets see what I'm sure of by now:
* 64 bits CPU is a must if you want more then 4GB ram (is 64b OS is required?)
* 64 bits CPU can accellerate games if compiled to use 64bits registers (how many % faster?)

I think >4GB ram will not be an issue for a long time, so what's left is 64b software
So what are the benefits of 64b software?

 

[FallOutBoyTonto]

This article might be able to answer your questions:

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[varghesejim]

64 bit processors are defenitely faster but for the time being it is not giving that much improvement,so you look for it after one year.Then wide software support will make it more reasonable to buy.

 

[imgod2u]

Again, it depends on which 64-bit processor. People automatically equate K8 with "64-bit processors". K8 includes much more than just "64-bitness" and therefore, it will also bring performance improvements, regardless of its "64-bitness".
As for what 64-bit will bring you. By definition, a 64-bit processor will:

1. Allow more than 4 GB of flat memory address. (You can have more than 4 GB of memory but it'll be extended via PAE).
2. Allow work on integers larger than 4 billion (useful in certain scientific and mathematical labs and also encryption)

"We are Microsoft, resistance is futile." - Bill Gates, 2015.

 

[c0d1f1ed]

* 64 bits CPU is a must if you want more then 4GB ram (is 64b OS is required?)

No. The only limitation of a 32-bit CPU is that each program can 'only' use 4 GB. So if you have 8 GB you will only use it optimally if you have several programs that each use several GB of RAM. No game needs 4 GB today so you're safe with a 32-bit CPU for some years.

* 64 bits CPU can accellerate games if compiled to use 64bits registers (how many % faster?)

They can indeed be faster. But that's -not- because it's 64-bit, it's because there are more registers. This allows frequently used data to stay in the registers so less memory accesses are needed. How much faster it will be depends on the application. Sometimes 8 registers is enough, sometimes 16 are a blessing.

On the other hand, more and longer registers means more complexity on the chip. Inherently this means it can be slightly slower. Or another way to look at it is that it will not clock as high.