Which Intel processors support Intel EM64T and when will they be available?
By Q4 of 2006, Intel EM64T will be supported in all mobile, desktop and server processors that are based on the Intel® Core™ microarchitecture. All Intel® Xeon® platforms based on the Intel NetBurst® microarchitecture will support Intel EM64T as well. Please refer to the processor product list for more information.

How does the performance of 64-bit Itanium® and 64-bit capable IA-32 processor based platforms compare?
The Itanium processor family is and will continue to be the highest performing and most reliable product family we offer for high-end, multi-processor systems. However, the performance differential is constantly changing due to the frequent release of new Itanium and IA-32 processor based platforms. Click here to find the latest performance ratings for all Intel products.

Is Intel EM64T the same technology used in the Itanium® 2 processor?
No. Intel EM64T is an extension to Intel's processors based on the IA-32 architecture. The Itanium processor family is based on the EPIC architecture. These are two separate families of processors, based on two different architectures. The Itanium processor family is specifically designed for the most demanding mission-critical applications.

Can the Itanium 2 IA-32 Execution Layer run the new Intel EM64T code?
At this time, the IA-32 Execution Layer does not support Intel EM64T binaries. Intel will evaluate providing this additional capability if and when customers request it.

Which O/S (Operating System) will support Intel's processors with Intel EM64T?
The following O/S vendors have available or announced product support for Intel EM64T. Contact each vendor for more details.


Microsoft:
Microsoft currently has two 64-bit operating systems that support Intel EM64T: Windows* Server 2003 x64 Edition and Windows* XP Professional x64 Edition. In addition, Microsoft will release the Windows* Vista operating system in 2007, which will also support Intel EM64T.
Apple:
Apple MAC OS* X Tiger, version 10.4.1 supports Intel EM64T.
Red Hat:
Redhat version 3.0 (and greater) supports Intel EM64T.
SuSE*:
SuSE 8.2 (and greater), SLES 8.0 and SLES 9.0 supports Intel® EM64T.
Sun Solaris*:
Solaris 10 x64/x86 supports Intel® EM64T.
FreeBSD:
FreeBSD version 6.0 supports Intel® EM64T.

Is it possible to write software that will run on Intel's processors with Intel EM64T, and AMD's 64-bit capable processors?
Yes, in most cases. Even though the hardware microarchitecture for each company's processor is different, the operating system and software ported to one processor will likely run on the other processor due to the close similarity of the instruction-set architectures. However, Intel processors support additional features, like the SSE3 instructions and Hyper-Threading Technology, which are not supported on non-Intel platforms. As such, we believe developers will achieve maximum performance and stability by designing specifically for Intel® architectures and by taking advantage of Intel's breadth of software tools and enabling services.

How will Intel EM64T work, and what software is there to take advantage of 64-bit extensions?
Development of a broad "ecosystem", ranging from processors, chipsets and tools to operating systems (O/S), applications, utilities and drivers is expected to take some time to develop. Platforms with Intel EM64T can be run in three basic ways (note: a 64-bit capable BIOS is required for all three scenarios):


32-bit O/S and 32-bit applications (Legacy Mode): No software changes are required, however the user gets no benefit from Intel EM64T.
64-bit O/S and 32-bit applications (Compatibility Mode): This usage requires all 64-bit device drivers. In this mode, the O/S will see the 64-bit extensions, but the 32-bit application will not. Existing 32-bit applications do not need to be recompiled, and may or may not benefit from the 64-bit extensions. The application will likely need to be recertified by the vendor to run on the new 64-bit extended O/S.
64-bit O/S and 64-bit applications (64-bit Mode): This usage requires 64-bit device drivers. It also requires applications to be modified for 64-bit operation and then recompiled and validated.

Will the Intel IA-32 processor with Intel EM64T have more registers than IA-32 processors today?
Yes, Intel's IA-32 processors with Intel EM64T have 16 General Purpose Registers (GPRs) and 16 XMM registers. The GPRs and XMM registers are 64 bits and 128 bits in width, respectively, in processors with Intel EM64T. The additional registers are only used by applications running in 64-bit mode. IA-32 processors without Intel EM64T have 8 GPRs and 8 XMM registers. The GPRs and XMM registers are 32 bits and 128 bits in width, respectively, in processors without Intel EM64T. More details can be found in the 64-bit Extension Technology Software Developer's Guide.

Will applications written for the Intel Itanium processor family run on Intel's IA-32 processors with Intel EM64T without being re-compiled?
No. The instruction sets for Intel's Itanium processor family are different than the IA-32 processor family. Applications need to be compiled separately for each processor family.

I have two platforms: one based on the Itanium processor family, and one based on an IA-32 architecture processor family with Intel EM64T. Will the same 64-bit operating system work on both platforms?
No. Different operating systems are required for each type of platform due to the different instruction set architectures. Contact your OS vendor to identify which operating system is needed for your particular platform configuration.

I have two platforms: one based on an IA-32 architecture processor family with Intel EM64T, and one based on an IA-32 architecture family without Intel EM64T. Will the same operating system work on both platforms?
Yes, if you are running a 32-bit operating system on both platforms. However, a 32-bit operating system will not take advantage of Intel EM64T.

If you want to take advantage of Intel EM64T, the first platform will need to run an operating system designed for 64-bit extensions. Operating systems for 64-bit extended systems will not run on the second platform. Contact your OS vendor to identify which operating system is needed for your particular platform configuration.

Does Intel EM64T include support for AMD's 3DNOW!* instructions?
No. Intel's IA-32 architecture does not support the 3DNOW! instruction set today. This has not changed with the addition of Intel EM64T.

What changes are needed for an IA-32 based platform to run a 64-bit O/S and 64-bit applications?
To run 64-bit applications and a 64-bit O/S, a platform will need an IA-32 processor with Intel EM64T, along with updated BIOS and drivers that have been modified for Intel EM64T. Contact your BIOS vendor and adapter vendor to get the BIOS and drivers that have been optimized for platforms with Intel EM64T.

Will existing 32-bit software run, without being re-compiled, on an IA-32 processor with Intel EM64T?
Yes, with some notes of caution. Refer to the 64-bit Extension Technology Software Developer's Guide for more details.

Running a 32-bit application on a 32-bit O/S, even with a processor with Intel EM64T, will execute without issue. With a 64-bit O/S and a 32-bit application the processor is designed to support this mode of operation completely (this is called compatibility mode). It is possible, however, that some applications may have certain dependencies beyond the processor's control (e.g. dependencies on the O/S or drivers) which may cause the applications to not run as expected.

Does Intel's Hyper-Threading Technology work in conjunction with Intel EM64T?
Yes. Both 32-bit and 64-bit applications can take advantage of the threading parallelism and performance improvements enabled with Intel's Hyper-Threading Technology.

Does Intel make available a compiler which will generate optimized code for Intel EM64T?
Yes. As of version 8.1, the Intel Fortran and C++ compiler for both Linux and Windows support Intel EM64T. For more information, click here.

Are software optimization tools available that support Intel EM64T?
Yes. Intel® VTune™, the Intel® Math Kernel Library (Intel® MKL), and Intel® Performance Primitives (Intel® IPP) all support Intel EM64T under Linux and Windows development environments. Additional VTune information can be found here. For Intel MKL and Intel IPP, information can be found here.

Where can I get applications that have been optimized for Intel EM64T?
Contact software vendors for their schedules, pricing and availability of applications compatible with Intel EM64T. Like any industry transition, we expect it to take time for applications to be ported to the 64-bit extended operating systems. By comparison, there are currently thousands of applications optimized for the Intel Itanium processor family. Some examples of currently available 64-bit applications can be found here* and here*.

Click here to Read the Full Article