This is a follow-up to this and this thread. There has been some talk of variation within drives, even within TLA series. There is of course not much to say if your drive is patently defective (bad vibrations, burning coasters on great media, etc.), but I wanted to relate an experience where both drives were satisfactory but one was much better than the other.
I purchased a TLA #0304, Made in China, February 2005 Plextor PX-716a from Fry's in Palo Alto about a week ago. I burned a few coasters that were probably related to my using a 40-pin IDE cable and hanging a hard drive as a slave off the same cable. Anyway, after fixing all that, I started burning OK discs from a PIE standpoint, but which were far from satisfactory in the TA tests. Even the PIE graphs paled by comparison to zevia's scan on the same media. Ultimately I decided that something wasn't quite right, so I went back to Fry's today and got a replacement drive. Incidentally, there was an 0203 on the shelves and I thought long and hard about whether to pick it up or not. Ultimately, I wanted to be able to provide some useful info to this forum and the only way to do that was to eliminate as many confounding factors as possible. Ceteris paribus, if you will.
What follows are scans of 8x burns of the same data with the old and new drives (referred to as OLD and NEW below) read by the new drive. This is the only consistent way to compare performance. In fact, the PIE scans made by the new drive are much worse (more representative of the quality of the disc) than the scans of the same disc on the old drive. This indicates that the read and write performance of a drive are highly correlated.
I hope this thread will serve to indicate how one might go about evaluating a new drive. Please exercise level-headed restraint: note that even my new PX-716a does not remotely approach the quality of zevia's scan on the same media (but with an older TLA), and that the SUM1 test is problematic. There may be 0304 drives out there with even better performance than mine, but I'm satisfied that I finally have a decently working drive. Nevertheless, I would be much obliged if someone with an 0304 model and ProdiscF01 discs could make an 8x burn and pass along a comparative scan .
And now, the scans.