User`s guide

Release 331 Graphics Drivers for Windows - Version 331.82 RN-W33182-02v01

Known Product Limitations

Poor Quality S-Video Output on Some TVs

NVIDIA drivers differentiate an S-video TV from a composite TV by searching for 75-

Ohm loads on the chrominance and luminance lines. If the driver detects only one such

load, it assumes that it has a composite TV and drives both chroma and luma onto that

line. This approach allows both types of TV to display in color.

Unfortunately, some S-video TVs do not apply the correct load to both lines, causing the

driver to detect an S-video TV as a composite. The driver, in turn, sends the lower quality

signal to the S-video TV. To work around this problem, use the Control Panel to override

the Auto-select feature. This can be done following these steps:

1 In the Settings tab of the Display Properties Control Panel, click Advanced.

2 In the nView tab, click Device Settings and click Select Output Device.

3 In the Device Selection tab, click the TV option.

4 Change the Video output format to S-video.

AGP and PCI-E Programs May Hang With AMD K7 and K8

Processors

 Issue

Microsoft® Windows® 2000 and Windows XP systems using AMD K7 and K8

processors can hang when an AGP or PCI-E program is used.

 Root Cause

There is a known problem with Microsoft® Windows® 2000 and Windows XP

systems using AMD K7 and K8 CPUs that results in the Microsoft operating system

allocating overlapping 4M cached pages with 4k write-combined pages. This

condition results in undefined behavior and data corruption, and is explicitly

disallowed by the AMD CPU manual.

This problem can affect any device driver in the system that allocates write-combined

system memory, but is usually most easily reproduced with graphics drivers since

graphics drivers generally make heavy use of write-combined system memory for

performance reasons.

 Resolution

Microsoft has a knowledge base article on the issue, the text of which is unfortunately

quite outdated. While the article only mentions Windows 2000, AGP, and K7, both the

root cause and resolution also apply to Windows 2000 or Windows XP, AGP or PCI-E,

and AMD K7 or K8. The article can be found at http://support.microsoft.com/

?id=270715.

The issue is resolved by applying an operating system registry key as described in the

referenced article that instructs the Microsoft operating system to not use the 4M

pages, thus avoiding the conflict.