I have a few 80-85oz (i think) steppers that I use on my home built cnc machine. I am using a pc power supply for these motors at 12 volts. Will higher voltage allow the motors to spin faster without stalling? Ive seen some videos on this site and it appears these motors are spinning quite a bit faster than mine. Is this due to motor type or could more voltage be a fix for me?

Thanks all!

Doubling the voltage will usually double your useable top speed.

But don't use higher voltage without some kind of current control in the form of a resistor unless you use a chopper drive and in that case the drive controls the current.
The stepper should run at all times with no more than the rated current, both methods of resistor and chopper prevent the optimum current being exceeded through the rpm range.
Al