ok guys, here's the results for new tests.
This one is with SMARTBURN enabled which limits writing to 16x on these media, Overburned to 707MB with mixed data (703MB capacity)
-
link
This one is at 40x with SMARTBURN off not overburned, 702MB mixed data burned.
-
link
is this better?
I have no idea what im supposed to look at for c1/c2 errors etc! but from this I can gather that SMARTBURN does indeed help when overburning or it's the lower writing speed on the media but at 40x NOT overburned the cd is also fine