Processor Types and Specifications - Upgrading and Repairing PCs - page 74

and A/V processing, scientific simulations, financial analytics, and 3D modeling and ana-
lysis to perform better. AVX is supported on Windows 7 SP1, Windows Server 2008 R2
SP1, and Linux kernel version 2.6.30 and higher. For AVX support on virtual machines
running on Windows Server R2, see http://support.microsoft.com/kb/2517374 for a hot-
fix.
For more information about AVX, see http://software.intel.com/en-us/avx/ . Although
AMD has adopted Intel SSE3 and earlier instructions in the past, instead of adopting
SSE4, AMD has created a different set of only four instructions it calls SSE4a. Although
AMD had planned to develop its own instruction set called SSE5 and release it as part of
its new “Bulldozer” processor architecture, it decided to shelve SSE5 and create new in-
struction sets that use coding compatible with AVX. The new instruction sets include
• XOP—integer vector instructions
• FMA4—floating point instructions
• CVT16—half-precision floating point conversion
3DNow!
3DNow! technology was originally introduced as AMD's alternative to the SSE instruc-
tions in the Intel processors. It included three generations: 3D Now!, Enhanced 3D Now!,
and Professional 3D Now! (which added full support for SSE). AMD announced in
August 2010 that it was dropping support for 3D Now!-specific instructions in upcoming
processors.
For more information about 3D Now!, see “ 3D Now ” in Chapter 3 of Upgrading and Re-
pairing PCs, 19 th edition , which is supplied on the disc packaged with this topic.
Dynamic Execution
First used in the P6 (or sixth-generation) processors, dynamic execution enables the pro-
cessor to execute more instructions in parallel, so tasks are completed more quickly. This
technology innovation is composed of three main elements:
• Multiple branch prediction —Predicts the flow of the program through several
branches
• Dataflow analysis —Schedules instructions to be executed when ready, independent
of their order in the original program
• Speculative execution —Increases the rate of execution by looking ahead of the pro-
gram counter and executing instructions that are likely to be necessary