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Troubleshooting Video Card Problems - Part 2: The BIOS
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Posted by: Ion Silverbolt
TROUBLESHOOTING VIDEO CARD PROBLEMS
PART 2: BIOS SETTINGS
- Solutions compiled by Paul Olinger, Jr (Ion Silverbolt)
In Part 1, we explored driver issues when it comes to troubleshooting video problems. When all that fails, sometimes a setting in your BIOS CMOS settings may help improve stability. This is where part 2 comes in. In this part, I will cover several CMOS settings that may improve stability and try to explain them in some detail.
ACCESSING THE BIOS
Accessing the BIOS varies depending on the make and model of your motherboard. Almost all modern motherboard BIOS settings are accessible by hitting the Delete key during POST. (Power On Self Test). This is where you see the memory being checked and the devices being initialized. Once you hit the Delete key, you should enter your CMOS setting screen.
Entering the BIOS may differ depending on your computer. Brandname PC's like Compaq, Dell, and Gateway may have other ways of entering the BIOS. Here's a list of common keys to get into your BIOS settings:
Delete or Del Most common way to enter BIOS.
Alt Enter Some Dell Models use this.
Ctrl Esc General
Ctrl Alt + General
F10 Some Compaq's use this.
Some BIOS settings are locked out by the PC manufacturer. So if you can't get into your BIOS settings, you may not be able to change anything. The best place to check if you're unsure is your motherboard manual, or check the onscreen messages on bootup. Sometimes they tell you which keys to hit to enter the BIOS. If it goes too fast for you to read, hit the Pause/Break key. This will stop the bootup until you hit the key again.
ENTERING THE BIOS SETUP
When you enter the BIOS, it should look something like the picture below:
http://www.opentechsupport.net/guid...ges/shots65.gif
Most BIOS screens are self explanatory on how to operate them. However, it's nice to have your motherboard manual handy so as to get an idea what each heading is for and what settings it covers. The settings we'll be going over are for users that have an Award BIOS. Most BIOS settings are setup by the motherboard manufacturer and some tend to vary a lot. The motherboard manual is nice to have handy to get an understanding of different settings. We'll cover the common ones most users have.
BIOS MENUS
This is where the settings will be covered. Some of them we will not explore since they don't contain any video specific settings. Almost all AGP related settings are in the Advanced BIOS setup and the Advanced Chipset Setup menus. Again these choices may vary depending on your motherboard or PC vendor. Check the manual if possible.
Read-Around-Write - This setting appears in many BIOS settings and improves memory read performance when enabled. Some graphics cards may behave erratic with this setting enabled. NVidia cards on VIA chipsets sometimes need this setting disabled. Especially older AGP cards and VIA chipsets.
System BIOS cacheable - This setting really doesn't affect video directly but disabling it frees up L2 cache on your processor which is a lot faster. Programs attempting to write to this memory area will also cause the system to crash. Leave it disabled.
Video BIOS Cacheable - This is similar to the above however it deals with the video BIOS. Again it wastes L2 cache bandwidth on the processor which is better served for other purposes. Windows OS platforms ignore calls to the BIOS anyway so this setting and the above one are useless. Programs that attempt to use this memory address will also cause the system to crash. Leave this setting disabled to free up video memory and reduce the chances of system lockup.
Video RAM Cacheable - This setting only appears if the above setting is enabled. It is better to have Video BIOS caching disabled.
AGP Aperture Size (MB) - This setting determines how much system memory will be dedicated to video performance. Memory allocated for this is faster than if the system has to access memory outside of this allocated amount. The best setting here is to set it to half the amount of RAM your computer has. So if you have 128 MB's, a setting of 64MB is good enough. If you have 256 megs of RAM or more and your graphics card only has 16 megs or less of RAM, try the 128MB setting. Graphic cards with 64 megs of onboard memory don't need a high AGP Aperture setting. 64 megs is enough in this case.
A setting of no less than 16MB AGP aperture size should not be selected. If your setup has less allocated, increase the amount to at least 16 if you only have 64 megs or RAM. If you have 128 megs, a setting of 64MB is good. For Windows 2000 with only 128 megs of RAM, the 32 setting would probably be better.
AGP Mode - This setting determines available bandwidth your AGP port will operate at. The settings are AGP X4, X2, and X1. It should be set no higher than your AGP card supports. If your card supports a higher speed such as AGP X4 or X2, setting it to a lower setting may improve graphics stability. X1 is still fast enough for most games. It's a setting worth changing if nothing else seems to help your graphics problem.
AGP Master 1WS Write - This setting reduces the wait state from two to one for AGP write transaction performance. Enabled, it will improve video performance. Disable this setting if you're having graphic card problems. Problems usually show themselves here in the form of corrupted graphics of some kind or weird pixelation.
AGP Master 1WS Read - This setting is similar to the above setting except it shortens the wait state for the AGP read transaction. Enable to improve performance. Disable it if you're having problems. Symptoms are similar to the above.
PCI Master 0 WS Write - This setting is normally disabled unless system problems are occurring with one or some of your PCI cards. Disabling this may help improve stability if a PCI card is acting up. (Usually a sound card or SB Live). Although not directly related to video, a lot of times video instability appears to be the culprit when it's actually something else causing the problem. Disable this setting after all other settings have failed.
AGP Driving Control - This setting is found on newer boards. It basically allows you to select the signal strength of the AGP port. Leave it set to Auto. Tweaking this setting may improve stability on an overclocked system. The best thing for normal clocked people is to leave this setting on auto.
AGP Fast Writes - Most of todays AGP graphics cards support this feature. It enables the fast write protocol for AGP X4 transfers. If your card doesn't do AGPX4, disable this feature. Also, disabling it may improve stability if you're having problems. If you change to X2 or X1, also disable this setting.
AGP Always Compensate - This is a dynamic compensation setting for the AGP Bus. Leave it enabled if you have it.
Super Bypass Mode - This is a setting found on motherboards using the AMD 751 and AMD761 Northbridges. When enabled, it allows the system controller to internally bypass certain memory pipeline stages for optimal performance. Enable it for better performance. Disable it if you're having problems. The AMD 751 in particular has issues with Geforce cards when this setting is enabled. Disable it if you have this configuration and are having problems.
USWC Write Posting - The USWC or Uncacheable Speculative Write Combination setting is found on most boards with AGP capability, this setting enabled may cause problems with graphics cards that do not support it. Even supported cards may have issues with it. Also, this setting enabled offers little performance boost and even decreases performance in some cases. If you're having problems, disable this setting.
CONCLUSION
Hopefully after going through the driver tips and then setting to compatible AGP settings in your BIOS, your graphics stability will have improved or been outright fixed. Unfortunately some issues can never be resolved. Usually because of a hardware incompatibility, or other problematic hardware of some kind. Then there's always the possibility of overheating or a bad power supply. I'll cover all those in Part 3 of this guide as well as other hardware issues that may cause video instability.
USEFUL LINKS
Speed Demonz BIOS Optimization Guide - Good place to learn about your BIOS.
Geforce(2) FAQ - Covers from the original Geforce to the Geforce 2.
- END OF PART 2
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