Gigabyte GA-965G-DS3 motherboard FAN setting disables i965G acceleration - needs caveat in Intel hardware matrix

[Bruce Perens]

Keith and Co.,

Changing a fan setting on my motherboard disables i965G acceleration. 
I'm not kidding.

Motherboard information:
    Manufacturer: Gigabyte Technology Co., Ltd.
    Product Name: 965G-DS3 (it says GA-965G-DS3 on the box)

BIOS Information
        Vendor: Award Software International, Inc.
        Version: F7
        Release Date: 01/11/2007

Report:

In the BIOS settings page for "PC Health Status", setting CPU Fan 
Control Method to "INTEL (R) QST" will disable the i965G acceleration. 
Flightgear goes from 15 FPS to 3.

Mechanism:

I think the BIOS implements this particular fan control method through 
memory-mapped I/O. 4 additional MTRRs are used when it is enabled, 
leaving insufficient MTRRs for X.

This needs a caveat in the hardware matrix for the Intel driver.

Keith, I think it would be appropriate for Intel to pursue this issue 
with Gigabyte, Award, or whoever writes this BIOS feature. This is a 
hidden trap-door that makes your chipset look bad.

    Thanks

    Bruce