What do you see in your Edit - Preferences - Performance panel?
Is the [ ] Use Graphics Processor setting not checked?
If you can't check it, chances are you need a display driver update, but it's possible your system is just not up to the task of providing Photoshop what it need to use your GPU.
It could be helpful if you'd go, in Photoshop, into the Help - System Info, copy the information in the first section, and paste it into a post here. That will allow folks to provide you more specific help on what you can do to get around this problem.
P.S., it's also possible you have your brush set to a very low flow rate or opacity, in which case the red brush shape overlay can be very, very light.