SUBSIM Radio Room Forums - View Single Post - Thinking to migrate to Vista X64(64 bit system) from XP 32 bit

goldorak · 01-13-09, 09:24 AM

Subman1, win32 applications on windows 64 (xp 64 or vista 64) are not emulated.
They run on top of the wow subsystem which takes care of converting the api 32 calls to api 64 calls. Nothing more, nothing less. So the impact on performance is very mild, its nothing like running the application on a virtual machine or having it emulated.

As for advantage of 64 bit systems. Its no only having access to more memory (4 GB on a 64 bit system is just as futile as 2 GB on a 32 bit system. You really need 8 GB or more to offset the increase in code size due to 64 bit pointers), the day you will be running NATIVE 64 bit applications you'll use much more registers (something that on x86 architectures has always been a little on the starving side) and performance will increase. Sure not 100% but performance will increase.

It is a good thing to go to 64 bit. And by the way C2D, Phenom etc... are all 64 bit processors. They are not hybrids. They can run native 64 bit applications, and 32 bit applications. Even 32 bit application on 64 bit os through the wow subsystem (on windows). Itanium is a 64 bit processor that runs native 64 bit code, but runs 32 bit code only through EMULATION and not through a wow-like subsystem. Thats one of the reasons that Intel ditched the idea of using an Itanium-like processor for the desktop. Performace in 32 bit code execution and the fact that AMD beat them to the 64 bit. They were the first to have a working implementation of 64 bit that didn't penalize 32bit execution. So Intel did the only thing possibile, it licensed the technology from AMD and used it in its C2D etc.. processors, and obviously killed the desktop itanium like project along the way.

01-13-09, 09:24 AM	#8
goldorak Admiral Join Date: Apr 2005 Posts: 2,320 Downloads: 0 Uploads: 0	Subman1, win32 applications on windows 64 (xp 64 or vista 64) are not emulated. They run on top of the wow subsystem which takes care of converting the api 32 calls to api 64 calls. Nothing more, nothing less. So the impact on performance is very mild, its nothing like running the application on a virtual machine or having it emulated. As for advantage of 64 bit systems. Its no only having access to more memory (4 GB on a 64 bit system is just as futile as 2 GB on a 32 bit system. You really need 8 GB or more to offset the increase in code size due to 64 bit pointers), the day you will be running NATIVE 64 bit applications you'll use much more registers (something that on x86 architectures has always been a little on the starving side) and performance will increase. Sure not 100% but performance will increase. It is a good thing to go to 64 bit. And by the way C2D, Phenom etc... are all 64 bit processors. They are not hybrids. They can run native 64 bit applications, and 32 bit applications. Even 32 bit application on 64 bit os through the wow subsystem (on windows). Itanium is a 64 bit processor that runs native 64 bit code, but runs 32 bit code only through EMULATION and not through a wow-like subsystem. Thats one of the reasons that Intel ditched the idea of using an Itanium-like processor for the desktop. Performace in 32 bit code execution and the fact that AMD beat them to the 64 bit. They were the first to have a working implementation of 64 bit that didn't penalize 32bit execution. So Intel did the only thing possibile, it licensed the technology from AMD and used it in its C2D etc.. processors, and obviously killed the desktop itanium like project along the way.