Windows 8? Update your video card drivers from the GPU maker's website.
I have recently seen similar problem where the whole canvas fills up with an average color whenever I am using marquee or lasso tools.
It looks as if PS is having a hard time showing the marquee selection borders in realtime.
I have seen this so far only in PS CC so i have been using PS CS6 for now.
I have only noticed this bug in CC only after the latest updated from creative cloud server.
In preferences i have separate disk set for scratch disk as well so my system is more than capable of handling big files with lot of layers.
In general i dont really have any performance issue though.
system: windows7 64bit, i7 3930k, AMD Firepro W7000, 32gb ram
all certified drivers updated.
HI chris tried this but the driver is already up to date. I am using windows 8 and according to the following reply from 8davinci8 its a common problem. might go back to CS6 too
Thanks for this I am still experienceing problems and will probably go back to CS6 too.