Datasheet

Identifying Motherboards 35
Some newer systems also have an L3 cache, which is an external cache on the mother-
board that sits between the CPU and RAM.
IDE and SCSI On-Motherboard Interfaces
Most motherboards include two integrated drive electronics (IDE) channels but don’t include
built-in Small Computer System Interface (SCSI). A consideration when choosing a mother-
board for IDE is that it needs to support the desired level of UltraDMA to match the capabili-
ties of the hard drive you want to use.
Chipsets
The chipset is the set of controller chips that monitors and directs the traffic on the mother-
board between the buses. It usually consists of two or more chips. Motherboards use two basic
chipset designs: the north/south bridge chipset and the hub chipset.
North/south bridge is the older of the two. The north bridge connects the system bus
to the other relatively fast buses (AGP and PCI). The south bridge connects ISA, IDE, and
USB. A third chip, SuperIO, connects the legacy parallel and serial ports.
The hub chipset includes a memory controller hub (equivalent to the north bridge), an
I/O controller hub (equivalent to the south bridge), and a SuperIO chip.
Troubleshooting Dislodged Chips and Cards
The inside of a computer is a harsh environment. The temperature inside the case of some
Pentium computers is well over 100° F! When you turn on your computer, it heats up. Turn
it off, and it cools down. After several hundred such cycles, some components can’t handle
the stress and begin to move out of their sockets. This phenomenon is known as chip creep,
and it can be really frustrating.
Chip creep can affect any socketed device, including ICs, RAM chips, and expansion
cards. The solution to chip creep is simple: open the case, and reseat the devices. It’s sur-
prising how often this is the solution to phantom problems of all sorts.
Another important item worth mentioning is an unresponsive but freshly unboxed PC.
With the introduction of the Type II and Type II-style processors, the number of dead
boxes increased dramatically. In fact, at that time I was leading a 2,000-unit migration
for a large financial institution. As with any large migration, time and labor were in short
supply. The average dead PC ratio was about 1 out of every 20. When about 10 DOAs had
stacked up, I stayed after work one night to assess the problem. After checking the power
supply, RAM, and cables on these integrated systems, an examination of the chip provided
me with the fix. These large, top-heavy processors can become dislodged during shipment.
Shortly thereafter, manufacturers began using a heavier attachment point for the slot style
of processor, which has helped tremendously.
CMOS
You can adjust a computer’s base-level settings through a Basic Input/Output System (BIOS)
Setup program, which you access by pressing a certain key at startup, such as F1 or Delete
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