Integrated graphics have stricter memory bandwidth limitations that restrict the resolution and refresh rate of the modes you request. To work around this, you can reduce the maximum refresh rate by lowering the upper value of the "VertRefresh" range in the Monitor section of your X config file. Though not recommended, you can disable the memory bandwidth test with the "NoBandWidthTest" X config file option.
Linux - warning message: Not using mode '1600x1200' (exceeds valid memory bandwidth usage)
Updated 09/29/2021 09:52 AM
I am using either nForce of nForce2 internal graphics, and I see
warnings like this in my X log file:
Not using mode "1600x1200" (exceeds valid memory bandwidth usage)