The difference between 32-bit and 64-bit Windows 7 and XP

x86 is the standard abbreviation for intel processor-based systems. X has nothing to do with the processor, it is a simple wildcard definition for all *86 systems, is a serial number of the intel general-purpose computer series, and also identifies a set of general computer instruction sets, because the CPU numbers of the early intel are as 8086, 80286 to number, because the entire series of CPUs are instruction-compatible, so they use X86 to identify the set of instructions used. Today's Pentium, P2, P4, Celeron series support X86 command system, so both Belongs to the X86 family.

The 64-bit technology here is relative to 32-bit. This bit refers to the CPU GPRs (General-Purpose Registers), which has a data width of 64 bits. The 64-bit instruction set is An instruction to run 64-bit data, which means that the processor can run 64-bit data at a time. 64bit processors are not available now. In the high-end RISC (Reduced Instruction Set Computing), there are 64bit processors, such as Sun's UltraSparc III, IBM's POWER5, HP's Alpha, etc. .

Simply say x86 stands for 32-bit operating system x64 stands for 64-bit operating system.

64bit computing has two main advantages: it can perform a larger range of integer operations; it can support larger memory. It is not easy to think that the performance of a 64-bit processor is twice that of a 32-bit processor because of the digital changes. In fact, in 32-bit applications, the performance of 32-bit processors will be even stronger. Even 64-bit processors are currently more powerful in 32-bit applications. So be aware of the advantages of 64bit processors, but not superb 64bit.

To achieve true 64-bit computing, a 64-bit processor is not enough. You must also have a 64-bit operating system and 64-bit application software. The three are indispensable. The lack of any of these elements is impossible to achieve 64-bit computing. At present, in terms of 64-bit processors, Intel and AMD processor manufacturers have released a series of 64-bit processors of various specifications; in terms of operating systems and application software, the current situation is not optimistic. Because the 64-bit operating system that is really suitable for personal use is now only Windows XP X64, and Windows XP X64 itself is just a transitional 64-bit operating system, it will be eliminated after the release of Windows Vista, and Windows XP X64 itself Not perfect, easy to use is not high, an obvious example is that the drivers of various hardware devices are not perfect, and now 64-bit application software is still basically not, indeed hardware manufacturers and software vendors are not willing to go for a A transitional operating system writes drivers and applications. So in order to achieve true 64-bit computing, I am afraid I have to wait until Windows Vista has been popular for some time.

The current 64-bit technologies used by mainstream CPUs include AMD's AMD 64-bit technology, Intel's EM64T technology, and Intel's IA-64 technology. Among them, IA-64 is independently developed by Intel and is not compatible with the current traditional 32-bit computer. It is only used for Itanium and subsequent products Itanium 2, which is not covered by general users, so it is only for AMD 64-bit technology and Intel. EM64T technology to do a brief introduction.

AMD64-bit technology

AMD64's bit technology is based on the original 32-bit X86 instruction set, adding X86-64 extended 64-bit X86 instruction set, making this chip hardware compatible The original 32-bit X86 software, while supporting X86-64 extended 64-bit computing, makes this chip a true 64-bit X86 chip. This is a true 64-bit standard and the X86-64 has 64-bit addressing.

The new set of CPU registers in the X86-64 will provide faster execution efficiency. Registers are places used internally by the CPU to create and store CPU operations and other computational results. The standard 32-bit x86 architecture includes eight general-purpose registers (GPRs), and AMD added eight more groups (R8-R9) to the X86-64, increasing the number of registers to sixteen. The X86-64 register defaults to 64-bit. Eight additional 128-bit XMM registers (also known as SSE registers, XMM8-XMM15) have been added that will provide more space for single instruction multiple data stream (SIMD) operations. These 128-bit registers will be provided in vector sum. 128-bit double precision processing in scalar calculation mode provides a hardware foundation for 3D modeling, vector analysis, and virtual reality implementation. By providing more registers, CPUs produced according to the X86-64 standard can process data more efficiently and can transfer more information in one clock cycle.

EM64T Technology

Intel officially defines EM64T as follows: EM64T full name Extended Memory 64 Technology, which is an extended 64bit memory technology. The EM64T is an extension of the Intel IA-32 architecture, the IA-32e (Intel Architectur-32 extension). With the addition of EM64T technology, the IA-32 processor allows software to utilize more memory address space while compatible with IA-32 software, and allows software to perform 32-bit linear address writes. The EM64T specifically emphasizes compatibility with 32-bit and 64-bit. Intel added eight 64-bit GPRs (R8-R15) to the new core and extended all of the original GRPs to 64 bits, which improves integer arithmetic as described earlier. Eight 128-bit SSE registers (XMM8-XMM15) are added to enhance multimedia performance, including support for SSE, SSE2, and SSE3.

Intel has designed two models for processors supporting EM64T technology: legacy IA-32 mode and IA-32e mode. In the processor supporting EM64T technology, there is a component called extended feature enable register (IA32_EFER), in which Bit10 controls whether EM64T is activated. Bit 10 is called IA-32e mode active or long mode active (LMA). When LMA=0, the processor operates as a standard 32-bit (IA32) processor in the traditional IA-32 mode; when LMA=1, the EM64T is activated and the processor runs in IA-32e extended mode. under.

At present, AMD supports 64-bit technology CPUs such as Athlon 64 series, Athlon FX series and Opteron series. Intel's CPUs supporting 64-bit technology include the Xeon series using Nocona core, the Pentium 4 6 series using Prescott 2M core, and the P4 EE series using Prescott 2M core.