Add to Reddit
BIOS Option Of The Week
Since 1999, we have been developing the BIOS Optimization Guide, affectionately known as the BOG. From a meager beginning of a single page, it now covers over 430 BIOS options. As old BOG readers will know, we started offering two editions of the BOG since Revision 8.0 - a simplified edition and the complete edition.
In the simplified edition, the description of each BIOS option in this guide is condensed and written in a simplified format. This simplified edition is not a sampler or demo version of the complete BIOS Optimization Guide. It is merely a simplified version with all the essential points and minus the frills.
The complete edition, on the other hand, features both simplified descriptions as well as full details of each BIOS option. This allows you to quickly get the gist of what each BIOS option mean and delve deeper into the details if you wish to learn more about it.
Normally, the complete edition is only available to subscribers who help sponsor the development of the guide through a small fee. However, that changes today! From now on, we will post a BIOS option from the complete edition of the BIOS Optimization Guide every weekend. We hope this will help you improve your knowledge of BIOS options. If you find the guide useful, be sure to tell your friends! 
This week, we will be taking a look at the Watchdog Timer BIOS option.
Watchdog Timer
Common Options : Enabled, Disabled
Quick Review
This BIOS feature controls the operation of the chipset's Watchdog Timer.
When enabled, the Watchdog Timer will monitor the time taken for each task performed by the operating system. Any timeout will cause it to initiate corrective actions like generate a non-maskable interrupt or reboot the computer.
When disabled, the Watchdog Timer will not monitor the time taken for each task performed by the operating system. Even if the system locks up, the Watchdog Timer will not initiate any corrective action.
It is recommended that you enable the Watchdog Timer to automatically detect hardware and software errors that lock up the computer. While it may do nothing more than automatically reboot or shutdown the computer when an irresolvable error occurs, there is a chance it may allow the correction of the problem and allow the computer to function normally.
Details
The Watchdog Timer (WDT) is an independent monitoring circuit built into the chipset to detect when a computer malfunctions due to a software or hardware error. It does this by employing a countdown timer that limits the amount of time a particular task is allowed to take.
Every time the operating system performs a task, the countdown timer keeps track of the amount of time taken. If the task cannot be completed within a pre-determined time, the Watchdog Timer assumes that the computer has locked up and initiates a number of actions. These may be attempts at correcting the problem, like generating a non-maskable interrupt; or the Watchdog Timer may just reboots or shut down the computer.
The WDT timer ticks approximately once every 0.6 seconds but there is a one-tick uncertainty. This means the very first timer tick may occur immediately when the timer is started or up to 0.6 seconds later.
By default, the WDT timer is set to 04h, which allows a timeout period of 1.8 to 2.4 seconds. The timer can be set up to a maximum value of 3Fh, which gives a timeout period of approximately 37.5 seconds.
This BIOS feature controls the operation of the chipset's Watchdog Timer.
When enabled, the Watchdog Timer will monitor the time taken for each task performed by the operating system. Any timeout will cause it to initiate corrective actions like generate a non-maskable interrupt or reboot the computer.
When disabled, the Watchdog Timer will not monitor the time taken for each task performed by the operating system. Even if the system locks up, the Watchdog Timer will not initiate any corrective action.
It is recommended that you enable the Watchdog Timer to automatically detect hardware and software errors that lock up the computer. While it may do nothing more than automatically reboot or shutdown the computer when an irresolvable error occurs, there is a chance it may allow the correction of the problem and allow the computer to function normally.
Support Tech ARP!
If you like our work, you can help support out work by visiting our sponsors, participate in the Tech ARP Forums, or even donate to our fund. Any help you can render is greatly appreciated!
Questions & Comments
Please feel free to post your questions or comments here!
| Date | Revision | Revision History |
| 01-12-2008 | 1.0 | Covered the Intel Turbo Mode Tech BIOS option. |
| 07-12-2008 | 1.1 | Covered the DRDY Timing BIOS option. |
| 14-12-2008 | 1.2 | Covered the ACPI 2.0 Support BIOS option. |
| 21-12-2008 | 1.3 | Covered the Overclock Recovery BIOS option. |
| 28-12-2008 | 1.4 | Covered the EXT-P2P's Discard Time BIOS option. |
| 04-01-2009 | 1.5 | Covered the Graphics Aperture Size BIOS option. |
| 11-01-2009 | 1.6 | Covered the Memory DQ Drive Strength BIOS option. |
| 18-01-2009 | 1.7 | Covered the PCI-E Maximum Payload Size BIOS option. |
| 25-01-2009 | 1.8 | Covered the Max Async Latency BIOS option. |
| 01-02-2009 | 1.9 | Covered the Chipkill BIOS option. |
| 08-02-2009 | 2.0 | Covered the PCI Delay Transaction BIOS option. |
| 15-02-2009 | 2.1 | Covered the MAC Media Interface BIOS option. |
| 22-02-2009 | 2.2 | Covered the Digital Locked Loop (DLL) BIOS option. |
| 01-03-2009 | 2.3 | Covered the PCI-E Max Read Request Size BIOS option. |
| 08-03-2009 | 2.4 | Covered the DBI Output for AGP Trans. BIOS option. |
| 15-03-2009 | 2.5 | Covered the V-Link Mode Selection BIOS option. |
| 21-03-2009 | 2.6 | Covered the Errata 94 Enhancement BIOS option. |
| 28-03-2009 | 2.7 | Covered the Errata 123 Enhancement BIOS option. |
| 05-04-2009 | 2.8 | Covered the Dynamic Idle Cycle Counter BIOS option. |
| 11-04-2009 | 2.9 | Covered the Gate A20 Option BIOS option. |
| 20-04-2009 | 3.0 | Covered the Split Lock Operations BIOS option. |
| 26-04-2009 | 3.1 | Covered the DOS Flat Mode BIOS option. |
| 03-05-2009 | 3.2 | Covered the FPU OPCODE Compatible Mode BIOS option. |
| 10-05-2009 | 3.3 | Covered the LD-Off Dram RD/WR Cycles BIOS option. |
| 17-05-2009 | 3.4 | Covered the Odd Divisor Correct BIOS option. |
| 24-05-2009 | 3.5 | Covered the No-Execute Memory Protect BIOS option. |
| 31-05-2009 | 3.6 | Covered the ISA Enable Bit BIOS option. |
| 07-06-2009 | 3.7 | Covered the Interrupt 19 Capture BIOS option. |
| 14-06-2009 | 3.8 | Covered the Internal Graphics Mode Select BIOS option. |
| 28-06-2009 | 3.9 | Covered the PCI 2.1 Compliance BIOS option. |
| 05-07-2009 | 4.0 | Covered the SATA AHCI Mode BIOS option. |
| 12-07-2009 | 4.1 | Covered the L1 Data Cache Context Mode BIOS option. |
| 09-08-2009 | 4.2 | Covered the Maximum Read Request Size BIOS option. |
| 16-08-2009 | 4.3 | Covered the Delay DRAM Read Latch BIOS option. |
| 23-08-2009 | 4.4 | Covered the No Mask of SBA FE BIOS option. |
| 29-08-2009 | 4.5 | Covered the CPU Fast String BIOS option. |
| 06-09-2009 | 4.6 | Covered the CPUID Maximum Value Limit BIOS option. |
| 19-09-2009 | 4.7 | Covered the CPU Hardware Prefetch BIOS option. |
| 27-09-2009 | 4.8 | Covered the CPU/DRAM CLK Synch CTL BIOS option. |
| 04-10-2009 | 4.9 | Covered the CPU Drive Strength BIOS option. |
| 18-10-2009 | 5.0 | Covered the CPU Direct Access FB BIOS option. |
| 24-10-2009 | 5.1 | Covered the CPU Adjacent Sector Prefetch BIOS option. |
| 01-11-2009 | 5.2 | Covered the Compatible FPU OPCODE BIOS option. |
| 08-11-2009 | 5.3 | Covered the Clock Throttle BIOS option. |
| 15-11-2009 | 5.4 | Covered the Byte Merge BIOS option. |
| 21-11-2009 | 5.5 | Covered the Burn-In Mode BIOS option. |
| 29-11-2009 | 5.6 | Covered the Boot To OS/2 BIOS option. |
| 06-12-2009 | 5.7 | Covered the Boot Up Floppy Seek BIOS option. |
| 13-12-2009 | 5.8 | Covered the Auto Turn Off PCI Clock Pin BIOS option. |
| 20-12-2009 | 5.9 | Covered the Athlon 4 SSED Instruction BIOS option. |
| 27-12-2009 | 6.0 | Covered the ATA(PI) 80-Pin Cable Detection BIOS option. |
| 02-01-2010 | 6.1 | Covered the AT Bus Clock BIOS option. |
| 17-01-2010 | 6.2 | Covered the Assign IRQ For VGA BIOS option. |
| 24-01-2010 | 6.3 | Covered the ASF Support BIOS option. |
| 31-01-2010 | 6.4 | Covered the APIC Function BIOS option. |
| 07-02-2010 | 6.5 | Covered the Anti-Virus Protection BIOS option. |
| 14-02-2010 | 6.6 | Covered the Anti-Dot Crawl BIOS option. |
| 21-02-2010 | 6.7 | Covered the AGPCLK / CPUCLK BIOS option. |
| 07-03-2010 | 6.8 | Covered the AGP to DRAM Prefetch BIOS option. |
| 14-03-2010 | 6.9 | Covered the AGP Secondary Lat Timer BIOS option. |
| 21-03-2010 | 7.0 | Covered the AGP Read Synchronization BIOS option. |
| 11-04-2010 | 7.1 | Covered the AGP Prefetch BIOS option. |
| 01-05-2010 | 7.2 | Covered the AGP Performance Control BIOS option. |
| 09-05-2010 | 7.3 | Covered the AGP/PCI Burn-in Mode BIOS option. |
| 16-05-2010 | 7.4 | Covered the AGP ISA Aliasing BIOS option. |
| 23-05-2010 | 7.5 | Covered the AGP Driving Value BIOS option. |
| 30-05-2010 | 7.6 | Covered the AGP Driving Control BIOS option. |
| 06-06-2010 | 7.7 | Covered the AGP Drive Strength BIOS option. |
| 13-06-2010 | 7.8 | Covered the AGP Always Compensate BIOS option. |
| 21-06-2010 | 7.9 | Covered the AGP 3.0 Calibration Cycle BIOS option. |
| 27-06-2010 | 8.0 | Covered the Adjacent Cache Line Prefetch BIOS option. |
| 04-07-2010 | 8.1 | Covered the ACPI SRAT Table BIOS option. |
| 11-07-2010 | 8.2 | Covered the Act Bank A to B CMD Delay BIOS option. |
| 18-07-2010 | 8.3 | Covered the ACPI APIC Function BIOS option. |
| 25-07-2010 | 8.4 | Covered the 2T Command BIOS option. |
| 31-07-2010 | 8.5 | Covered the XD Technology BIOS option. |
| 08-08-2010 | 8.6 | Covered the Write Recovery Time BIOS option. |
| 15-08-2010 | 8.7 | Covered the Write Data In to Read Delay BIOS option. |
| 29-08-2010 | 8.8 | Covered the Write CAS Latency (Twcl) BIOS option. |
| 05-09-2010 | 8.9 | Covered the Watchdog Timer BIOS option. |
