if the secondary gpu is broken will that affect anything?
If I had to guess; and the functionality of the one graphics card is failing than I would think that the initialization process will just look at the card that is broken (confirm that it's non-functional) and move on to the next one that is functioning.
If your pretty certain that the one graphic card isn't funtioning properly; when you get the chance you might want to remove it from the motherboard. If it's a laptop than it might be a little more intresting to disesemble than a desktop.
If you know which driver is assisting your graphics card you could try to dmseg the driver and read through the output and see if there is any confirmation that the card is done for.
dmesg | grep (name of driver)
Driver's and modules are listed in the output of the command lsmod
reading through all of the output is still something I'm still learning to ensure that the modules/drivers are loading properly.
Glad to hear that your getting good use out of a pentium.
I studied that if you put a pentium and a celeron next to each other they tick at different beats.
Aside from that I think a pentium (if I recall correctly) has is about 30 % more front bus speed than a celeron.
So...that's good for you.
I've never tried Pclinuxos. What's it like?
What distribution are you actually running on your free machine?