Page 99 - A Practical Guide from Design Planning to Manufacturing

Design Planning 75

them as well. These designs will push die size and power levels to the
limits of what the desktop market will bear. The mainstream desktop
market tries to balance cost and performance, and these processor
designs must weigh each performance enhancement against the increase
in cost or power. Value processors are targeted at low-cost desktop sys-
tems, providing less performance but at dramatically lower prices. These
designs typically start with a hard cost target and try to provide the most
performance possible while keeping cost the priority.
Until recently mobile processors were simply desktop processors repack-
aged and run at lower frequencies and voltages to reduce power, but the
extremely rapid growth of the mobile computer market has led to many
designs created specifically for mobile applications. Some of these are
designed for “desktop replacement” notebook computers. These notebooks
are expected to provide the same level of performance as a desktop com-
puter, but sacrifice on battery life. They provide portability but need to
be plugged in most of the time. These processors must have low enough
power to be successfully cooled in a notebook case but try to provide the
same performance as desktop processors. Other power-optimized proces-
sors are intended for mobile computers that will typically be run off bat-
teries. These designs will start with a hard power target and try to provide
the most performance within their power budget.
Embedded processors are used inside products other than computers.
Mobile handheld electronics such as Personal Digital Assistants (PDAs),
MP3 players, and cell phones require ultralow power processors, which need
no special cooling. The lowest cost embedded processors are used in a huge
variety of products from microwaves to washing machines. Many of these
products need very little performance and choose a processor based mainly
on cost. Microprocessor markets are summarized in Table 3-1.

TABLE 3-1 Microprocessor Markets
Market Product Priorities
Server High-end server Performance, reliability, and multiprocessing
2U & 1U server Performance, reliability, and multiprocessing
within power limit
Desktop High-end desktop Performance
Mainstream desktop Balanced performance and cost
Value desktop Lowest cost at required performance
Mobile Mobile desktop Performance within power limit
replacement
Mobile battery Power and performance
optimized
Embedded Mobile handheld Ultralow power
Consumer electronics Lowest cost at required performance
and appliances