windows 7 64 bit?

[Joker]

dashing.sujay...u are completely wrong about any kind of performance degradation due to any kind of simulation/emulation while running x86 software on x86-64

Yeah, that simulation plays a very imp role in degrading performance of a 32-bit app over a 64-bit app. Though, In case of Itanium its totally diff case. It has got a separate 32 bit core to handle that.

dont know what u are talking here. separate 32 bit core..lolwut?

yup...'virtual' 10% gain is (can be) there because of x86-64..every poster is aware of that. 40% was a huge number you said.

 

[dashing.sujay]

I know 40% was much but I remember I read it somewhere

Other software must also be ported to use the new capabilities; older software is usually supported through either a hardware compatibility mode (in which the new processors support the older 32-bit version of the instruction set as well as the 64-bit version), through software emulation, or by the actual implementation of a 32-bit processor core within the 64-bit processor (as with the Itanium processors from Intel, which include an IA-32 processor core to run 32-bit x86 applications)

Above quote made me confused about simulation though.

 

[Cilus]

I don't understand why you guys are bringing IA-64 and IA-32 architecture here where we are discussing about X86-64 architecture. The software simulator for running 32 bit apps are required in IA-64 architecture which is completely different from X86-64 design.
For resolving that issue as well as some performance improvement, Intel sequentially included various IA-32 instruction supports directly to the IA-64 bt processors, they didn't include any separate 32 bit core for it.

As Joker said, there is no performance loss to run an existing X86 based programs to X86-64 architecture and it is the main reason that these approach has became the predominant 64 bit architecture now, because of the better adaptability with the existing architectur.