System Management BIOS FAQ

Your computer's System Management BIOS (SMBIOS) is responsible for reporting configuration data to diagnostic programs such as PC Pitstop. When this data has not been recorded correctly by the system maker, it can cause our reports to be incorrect. We cover some of the most common situations below.

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Why does PC Pitstop show incorrect system information?

PC Pitstop's utilities get much of their information from the system BIOS, which keeps tables specifying the processor type and memory configuration. In some cases, this information is not recorded correctly by the BIOS and we cannot determine that the BIOS information is incorrect. Common data problems include:

  • System brand or model is incorrect (e.g., "System Manufacturer")
  • System type shown as desktop when it's a notebook
  • Incorrect number of free or filled memory slots
  • Incorrect memory type or maximum module size

PC makers are supposed to use the System Management BIOS (SMBIOS) Specification to provide a way for utilities such as ours to get information about the PC. Older PCs built before about 1998 usually do not implement SMBIOS at all; PCs built before 2000 often have serious inaccuracies in their data. Even brand-new systems can have incorrect SMBIOS data, and it is common with many systems that are not from brand-name manufacturers.

Why does PC Pitstop say the CPU cache is disabled?

This is another sign of incorrect SMBIOS data. The SMBIOS indicates that a CPU cache is present, but that it is disabled. We have no way to know that the BIOS is giving incorrect information.

How does incorrect SMBIOS affect my system?

Usually, it has no impact on functionality or performance. SMBIOS data is intended for use by inventory and diagnostic programs. Microsoft Windows does not depend on SMBIOS information to be able to run properly. However, incorrect SMBIOS data can be a sign that the system maker did not do some basic quality control. If they did not get the SMBIOS data right, there is certainly a chance that they made other mistakes.

How can I see all the SMBIOS data?

PC Pitstop has a utility that will dump out all the information to a text file. To interpret the data you will need a copy of the SMBIOS specification (see below). You can download our utility at ftp://ftp.pcpitstop.com/pcpbios.zip.

Can I fix problems with incorrect SMBIOS data?

BIOS and system makers have utilities that can write to the SMBIOS data areas, but they do not usually make them available to end users. Sometimes the problems with SMBIOS are fixed through BIOS updates that will be made available by your system vendor or the manufacturer of the system board. If you cannot get a copy of the vendor's SMBIOS utility and a BIOS reflash does not solve the problem, then you will have to live with the data being wrong.

Where can I find out more about SMBIOS?

SMBIOS (also known as the DMI BIOS) is part of the work of the Distributed Management Task Force (DMTF). The SMBIOS specification is available on their web site at http://www.dmtf.org/standards/bios.php.