Hardware Reference
In-Depth Information
Tip
The current speed of a processor might not be its actual rated speed, either because of
overclocking or because some recent systems reduce processor speed when the system is not
heavily tasked. Both Intel and AMD have developed software tools that can properly identify
the rated speed of a processor.
For newer Intel processors, use the Intel Processor Identification Utility; for older chips, use
the Intel Processor Frequency ID Utility. Both of these are available from
For AMD processors, use either the AMD CPU Info program or the AMD Clock program. To
find these, visit
http://support.amd.com
, select Drivers and Downloads, All Processors. Then
search for
CPU info
and
AMD Clock
.
One drawback of the Intel and AMD programs is that they only work on their respective brands
of chips. Another excellent utility that works on both Intel and AMD processors is the CPU-Z
program available from
www.cpuid.com
. I routinely install this program on any systems I
build or service because it provides universal processor (and chipset) identification. See
example readouts earlier in this chapter.
Users who overclock their systems purchase chips rated at lower speeds and essentially do their own
testing to see if they will run at higher speeds. They can also start with the highest-rated chips and see
whether they can run them even faster, but success there is much more limited. The most successful
overclocking is almost always with the lowest-rated speed of a given design, and those chips are also
sold for the lowest price. In other words, statistically you might be able to find many of the lowest-
speed grade chips that are capable of running at the highest-speed grade (because they are essentially
identical during manufacture); however, if you start with the highest-speed grade, you might be able to
increase the speed only a small percentage.
Just remember that a difference exists between the rated speed of a chip and the actual maximum
speed at which it runs. Manufacturers such as Intel and AMD have to be conservative when they rate
chips, so a chip of a given rating is almost always capable of running at least some margin of speed
faster than the rating—the question is, how much faster? Unfortunately, the only way to know that is
by trying it out—that is, by testing chips individually.
Unlocking Cores
A variation of overclocking is the unlocking of disabled cores on AMD Phenom II and Athlon II
processors for better performance in single-threaded and multithreaded applications and when
multitasking. As
Table 3.24
indicates, many of AMD's X3 and X2 K10-based processors are based
on X4 designs that have one or two cores disabled.
If you unlock these cores using a method such as enabling the Advanced Clock Calibration (ACC)
feature in the system BIOS (see
www.tomshardware.com/reviews/unlock-phenom-ii,2273-5.html
for
details), one of the following results can take place:
• The unlocked core may function perfectly. This is the result if a core were disabled strictly to
enable the chip to be sold as an X3 rather than an X4.
• Your system boots and runs normally, but the “unlocked” core can't be detected or used. A core
disabled because of moderate problems would result in this problem.
