DBoulay, what burning software do you use?
In my experience, CD burn with PX-716A and Roxio Easy Media Creator 7.1 is slow and troublesome. 4x, 8x and 'PowerRec speed (1-48x)' are selectable (not PoweRec, lol). But with PowerRec speed, actual burning speed is only 8x. Furthermore, compatibility of this 8x burned CD-R is quite bad. C1/C2 is low, but many CD/DVD-ROM drives cannot mount this media.
With other burning software, such as DiscJuggler4.1.1151, Nero 184.108.40.206, ONES 2.0.297, there is no problem.