Information Technology Reference
In-Depth Information
word size The number of bits that the CPU can
accept as input simultaneously.
A CPU's word size also makes a difference. The word size is the num-
ber of bits that the CPU (or a single core of the CPU, if multi-core) can
accept as input simultaneously. Most desktop and notebook PCs have
64-bit CPUs, but some tablets, netbooks, and smartphones have 32-bit
CPUs; see Figure 2.2.
Figure.2 2 A 64-bit CPU has twice the word size of a 32-bit CPU, so the 64-bit CPU can
theoretically input and output date at twice the rate. In actual use, many other factors also
play a part, so the performance boost is less than 2x.
Windows 7 comes in both 32-bit (x86) and 64-bit (x64) versions. When selecting a copy of Windows for a
device, keep in mind that 32-bit CPUs can only run the 32-bit version of Windows. 64-bit CPUs can run either
64-bit or 32-bit versions of Windows, but run better with the 64-bit.
TIP
Because modern CPUs have many technology improvements in them,
speed and word size alone do not form a reliable benchmark of a CPU's
capability. Another way to look at performance is how many instructions
per second the CPU can process.
benchmark A consistent measurement of
performance.
instructions per second A measurement of a
CPU's throughput capability, taking into consider-
ation factors such as number of cores and latency.
The two largest manufacturers of CPUs are the companies Intel and
Advanced Micro Devices (AMD). Their CPUs are roughly equivalent in
performance level, but the internal architectures of the CPUs are differ-
ent. A motherboard will support one or the other, but not both. Some
people prefer one brand over the other, and claim that one brand or
model is superior for using a certain kind of software. Such claims are a
moving target, though, as each company continues to develop new and
better CPUs.
Quick Review
1  What are the three main components inside a CPU?
2  What is the purpose of a cache?
3  What is a multi-core CPU?
Search WWH ::




Custom Search