CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [41]
* * *
EXAM TIP You can determine your Windows version by right-clicking My Computer in Windows 2000 or XP, or Computer in Vista and Windows 7, and selecting Properties.
Figure 4-10 Vista Home Premium Media Center
Figure 4-11 Vista Ultimate
Enter 64-bit Windows
From roughly 1986 to around 2001, all CPUs were 32-bit. While we will save the big discussion of what 32-bit means for Chapter 5, “Microprocessors,” for now let’s keep it simple: a 32-bit CPU can only use a maximum of 4 gigabytes of RAM (232 = 4,294,967,296). Starting in 2001 we began to see 64-bit CPUs that could accept more than 4 gigabytes. 64-bit CPUs are now extremely common.
* * *
NOTE CPUs and 32- and 64-bit processing are covered in much greater detail in Chapter 5, “Microprocessors.”
The leap from 32-bit to 64-bit processing has a number of advantages. The really big compelling reason to go from 32- to 64-bit is that 64-bit CPUs support more than 4 gigabytes of RAM. The more RAM you have, the more programs—and the bigger the programs—your system will run. Until fairly recently, not too many of us cared to go above 4 gigabytes of RAM. We didn’t need the RAM and we didn’t have a CPU that could run at 64-bits. My, how things have changed over the past few years!
* * *
EXAM TIP Remember for the exams that 32-bit CPUs can support up to 4 GB of RAM. In concept, 64-bit CPUs can support up to 16 terabytes of memory, although you certainly won’t find that much memory in the typical PC.
The 64-bit CPUs first showed up with the Intel Itanium back in 2001. At that time the only folks interested in 64-bit processing were large data centers and a few organizations that needed to crunch big numbers. To run a computer with an Itanium, you needed an operating system that worked with a 64-bit processor. Up to this point, every version of Windows only ran at 32-bit. Microsoft answered the call by creating special 64-bit versions of Windows 2000 and XP, but these 64-bit versions of Windows 2000 were very rare.
In 2003, Advanced Micro Devices (AMD) started to ship the popular Athlon 64 CPU. This CPU could run in either 32-bit or 64-bit mode, making 64-bit a realistic option for most of us. Intel followed AMD around 2004 with Pentium 4 CPUs also capable of 32-bit or 64-bit processing. Since then, almost every CPU sold by Intel or AMD has the ability to run in either 32-bit or 64-bit mode. Moving from the 32-bit to the 64-bit world is easy, but only if you have a version of Windows to support 64-bit. Microsoft has multiple versions of Windows designed to support 64-bit CPUs.
* * *
NOTE All 32-bit versions of Windows support a maximum of 4 gigabytes of RAM. If your PC has more than 4 gigabytes and you’re not running 64-bit Windows, you might as well remove any RAM above 4 gigabytes. You’re wasting it!
Windows XP 64-bit Versions
The 64-bit-only version of Windows XP was called Windows XP 64-bit Edition (apparently Microsoft decided not to get cute when naming that one). Given that it only worked on Intel Itanium processors, the chance of your seeing this operating system is pretty small unless you decide to work in a place with powerful server needs. The Windows XP Professional x64 Edition is much more common, as it runs on any AMD or Intel processor that supports both 32 and 64 bits (Figure 4-12).
Figure 4-12 Windows XP Professional x64 Edition
Windows XP 64-bit versions have had some impact, as they were the first stable Windows versions that truly supported 64-bit processing, but it was the introduction of Microsoft Vista that really started the move into the 64-bit world.
Windows Vista 64-bit Versions
Every one of the earlier listed Vista versions comes in both a 32-bit and 64-bit versions. As we move into PCs with more than 4 gigabytes of RAM, it’s important to make sure your version of Windows is a 64-bit version (Figure 4-13).
Figure 4-13 64-bit Vista
* * *
NOTE