Datawrite have 2 sorts of media, usually both on the same spindle as I found out
Grey top Titanium -R’s - I have a spindle of 50. 10 are able to be burnt upto 16x with less than 10 PIF peaks (usually alot lower), 40 are only burnable at 2.4x or I get POF’s (a few even give POF’s at 2.4x). All errors start at the 3GB mark and the scan looks like a nice ski slope that just gets higher and higher till it errors out.
Datawrite are not the best discs. I have had alot of problems with variable quality from them and this has now put me off from buying any more.