Chapter 2 Solutions
Answers to Key Term Quiz
1. The external data bus allows the CPU to communicate with the motherboard and
other devices in the computer.
2. By lifting the arm on the Zero Insertion Force (ZIF) socket, you can easily install a
PGA CPU.
3. The computer uses the binary numbering system.
4. A CPU can run at any speed, as long as that speed does not exceed its clock speed.
5. Registers are areas inside the CPU where it temporarily stores internal commands and
data while it is processing them.
6. Divided into L1 and L2, a cache consists of small amount of SRAM that serves as a
holding area to provide data to the CPU faster than getting it from regular memory or
when regular RAM is unavailable due to refreshes.
7. If you know the number of wires in the CPU’s address bus, you know the maximum
amount of RAM that a particular CPU can handle.
8. A clock multiplying CPU runs at a faster speed internally and at a slower speed
externally when using the address bus and the external data bus.
9. Especially designed for laptops, a mobile CPU usually run at only about 75 percent
the speed of a desktop CPU.
10. The backside bus connects the CPU to the L2 cache.
Answers to Multiple Choice Quiz
1. B. (With its unique SPGA case, the only microprocessor that fits into Socket 8 is the
Pentium Pro.)
2. B. (All the following kinds of memory store data by using microscopic capacitors that
must be refreshed except SDRAM.)
3. A. (The address bus allows the CPU to communicate with the Northbridge.)
4. B. (Often regarded as the prototype for later CPUs, the Pentium Pro was the first
microprocessor to include both an L1 and an L2 cache.)
5. C. (The new 64-bit processors will expand the address bus, the only part of the
computer that is not currently 64-bits.) Page 72
6. A. (CPU speed is measured in megahertz and gigahertz, while RAM capacity is
measured in megabytes and gigabytes.)
7. D. (The Pentium 4 uses a 20-step pipeline and a quadrupled frontside bus that allows
four data transfers per clock cycle.)
8. D. (The first processor to use a 200 or 233 MHz system bus (or frontside bus) was the
AMD Athlon.)
9. C. (Designed to support from four to eight processors, the Xeon MP CPU also
features a large level 3 cache.)
10. B. (Replacing the CPU may not be the upgrade that is most cost-effective or that has
the strongest impact on your system’s performance.)
11. C. (The Athlon processor comes in a SEC package that fits into Slot A.)
12. B. (The main difference between the Itanium and the Opteron is that the Itanium can
run only 64-bit code while the Opteron can run both 32-bit and 64-bit code.)
13. A. (Intel produces the Celeron as a low-end processor and the Xeon as a high-end
processor.)
14. D. (If you have a 133 MHz system bus and your CPU runs at 2.53 GHz, the CPU
multiplier is 19.)
15. C. (If you change the CPU, you may also have to set jumpers or switches on the
motherboard for all of the following except the address bus.)
Answers to Essay Quiz
1. Among the features that allow a CPU to stay cooler are lowering the voltage. As
less power is used, less heat is generated. By splitting the voltage and reducing the
voltage even more at the core of the processor, it stays even cooler. Power-management
techniques such as System Management Mode (SMM) also save power and keep the
CPU cooler. In spite of these advances, external cooling devices are still necessary. A
CPU fan or a heat sink or a combination fan/heat sink are essential. Different kinds of
CPUs require different kinds of fans/heat sinks. It is important to select the fan/heat sink
appropriate for your processor. A small amount of heat sink compound will ensure a
good connection between the CPU and the device. It is also important that you plug the
CPU fan into the power connection. Liquid-cooling techniques are now available to
better cool the processors. Another important consideration is that the CPU clock speed is
set appropriately since over-clocking builds up additional heat.
2. Laptops have unique needs. The processors must be smaller, use less power, and
run cooler than desktop CPUs because there is no space in the laptop for large heat sinks
or fans. Because of these considerations, mobile CPUs typically run at only about 75
percent of the speed of their desktop counterparts.
3. The Celeron uses a 700 MHz processor while the Athlon has a faster 800 MHz
CPU. The system bus for the Celeron is 100 MHz while the Athlon has a faster 200 MHz
system bus. The L1 cache of the Celeron is only 32 KB while the Athlon features a larger
128 KB L1 cache. Similarly, the Celeron L2 cache is only 128 KB while the Athlon
offers a larger 512 KB L2 cache. Finally, the Celeron has only 128 MB of RAM while
the Athlon offers twice that amount, 256 MB of RAM. In comparing these two used
computers, it is obvious that the Athlon is a better computer.
4. The system bus allows the CPU to communicate with the rest of the computer
components. The address bus determines how much RAM the CPU can use with the
larger the number of wires in the address bus, the greater the amount of RAM the CPU
can address. The backside bus connects the CPU with the L2 cache. The frontside bus
connects the CPU with the RAM or with the Northbridge.
5. A clock-multiplying CPU runs at a faster speed internally than it does externally.
If it could not access data quickly enough, the faster internal speed would be wasted.
Since the RAM must be closed for refresh, the faster cache is able to pass data to the
CPU even when RAM is not directly available. A cache is merely a holding place to
speed up a slow device such as DRAM. It consists of a small amount of expensive static
RAM (SRAM). An L1 or internal cache is built into the CPU itself and is the first place
that the CPU looks for data. The L1 cache is also faster than the L2 cache. Placed either
on the motherboard or inside the CPU package, the L2 cache is slower than the L1 cache.
However, the L2 cache is much larger than the L1 cache.