Hardware Reference
In-Depth Information
As you can see from
Figure 20.10
, AGP 4X or 8X (1.5V) cards fit only in 1.5V or universal (3.3V or
1.5V) slots. Due to the design of the connector and card keys, a 1.5V card cannot be inserted into a
3.3V slot. So, if your new AGP card won't fit in the AGP slot in your existing motherboard, consider
that a good thing because, if you were able to plug it in, you would have fried both the card and the
board! In a case such as this, return the AGP 4X/8X card and check surplus outlets or eBay for a
compatible card.
I installed an upgraded processor, but it won't work.
First, make sure the motherboard supports the processor that is installed. Also make sure you are
using the latest BIOS for your motherboard; check with the motherboard manufacturer to see whether
any updates are available for download, and install them if any are available. Check the jumper
settings (older boards) or BIOS Setup screens to verify that the processor is properly identified and
set properly with respect to the FSB (or CPU bus) speed, clock multiplier, and voltage settings. On
some systems, you may need to press Ctrl+F1 or some other special key combination in the system
BIOS to display the setup screens used to configure processor and memory timings.
Make sure the processor is set to run at its rated speed and is not overclocked. If any of the CPU
settings in the BIOS Setup are on manual override, set them to automatic instead. Then reseat the
processor in the socket. Next, make sure the heatsink is properly installed and you are using thermal
interface material (that is, thermal grease) at the mating junction between the CPU and heatsink.
Just because a processor fits in the socket (or slot) on your motherboard does not mean it will work.
For a processor to work in a system, the following things are required:
• The CPU must fit in the socket. Refer to
Chapter 3
, “
Processor Types and Specifications
,
” for a
complete guide to the various CPU socket types and which processors are compatible with
them.
• The motherboard must support the voltage required by the CPU. Modern motherboards set
voltages by reading voltage ID (VID) pins on the processor and then setting the onboard voltage
regulator module (VRM) to the appropriate settings. Older boards might not support the
generally lower voltage requirements of newer processors.
• The motherboard ROM BIOS must support the CPU. Modern boards also read the CPU to
determine the proper FSB (or CPU bus) speed settings as well as the clock multiplier settings
for the CPU. Many CPUs have different requirements for cache settings and initialization, as
well as for bug fixes and workarounds.
• The motherboard chipset must support the CPU. In some cases, specific chipset models or
revisions might be required to support certain processors.
Before purchasing an upgraded processor for your system, you should first check with the
motherboard manufacturer to see whether your board supports the processor. If so, it will meet all the
requirements listed previously. Often, BIOS updates are available that enable newer processors to be
supported in older boards, beyond what was originally listed in the manual when you purchased the
board. The only way to know for sure is to check with the motherboard manufacturer for updated
information regarding supported processors for a particular board.
In one example, I had purchased a new motherboard and processor for a new system build, and upon
initial power-on, the system didn't work at all. Upon investigation, I found that the new motherboard I
had purchased did indeed support the processor I had installed, but only if the BIOS was upgraded to
the latest version. Unfortunately the board I had must have been sitting on the shelf awhile because it
