deimos wrote:

Many professional applications like the ones I work with actually have
some code for Quadro specific detection that goes beyond just the driver
or device ID, so there must be an API method of detecting Quadro
features other than just DXCaps or GL extensions.

No, but you are right in that it is the GL extensions recognition that
make up the bulk of the performance difference betwixt the two cards.

The chippies are the same: both CUDA GPUs, it's the drivers that are
different, different capabilities and ways of using the circuitry.

Also, a minor but interesting point, Quadros are severely stressed
before being put into the channel, the blue screen and nv4_disp.dll
errors that GeForce users see with too much frequency (for any reason)
you just don't get with Quadros, they are designed to be flawless 24/7,
like a CPU.