PX-708A 1.01 DVD+RW problems with reading speed

I have PX-708A DVD burner for two weeks now, and have experienced some reading problems with DVD+RW media burned on PX-708A. Using Ahead CDSpeed tool (tested with few versions) I have discovered that reading speed for every DVD+RW media burned on PX-708A drops from 6-7-8x to under 2x at the end of the disc (somewhere around 4 GB point and beyond). Tested DVD+RW media; Sony 2,4x, Philips 2,4x, HP 2,4x, Verbatim 2,4x, Memorex 2,4x. Used software: Ahead Nero, (latest), Ulead DVD Workshop 1.2,
and Ahead Nero shipped with burner (I think it’s version). Writer is shipped with 1.01 firmware, retail box, OS is Win XP SP1, 2,4GHz P4, 1 GB DDR333 RAM, RAID HD, Abit BE7-RAID MB, Enermax 350W PFC, Radeon 9700 and so on. Tried everything. Plextools, PowerREC enabled and disabled, different
settings in Nero. DVD+RW media were tested in PX-708A, PX-116A and HP200i. The same problem exists everywhere. Well, every media is actually readable at the end of the story, but speed drops and You can also see that during any file transfer. The same media burned on my old HP200i doesn’t suffer of that problem. So, what’s wrong ? Any idea ? Different brands of
DVD+R media doesn’t have that problem.

i have the same problem!plex support told me that i have problems in pc system.but with the dru500a i have no probs.

Well, I have mail them the same report I posted here, so maybe now they could get some idea. Anyway, just burned fresh new Memorex 2,4x DVD+RW (Nero, UDF data, compilation loaded to the top). Tested with CDSpeed, hm, returned perfect curve this time :-! Also burned another Sony and Verbatim DVD+RW (both 2,4x), and the problem seems to be much lower with Verbatim where speed at the end drops just a little bit. But with Sony speed drops from 8x to 3x at the end again. Sony media is actually Ricoh, and I read allready from some posts here that Ricoh media is generally not so friendly to PX-708A. However, Sony DVD+R, 2,4 and 4x, Ricoh, works flowlesly burned at 2,4 and 4x.