Why is Compressor 4 so darned slow?

Question

Hello all,
Using Compressor 4.0.6 and FCX 10.0.7.  Have a few iMac's, all core i7's, 2011 or later, all with a minimum 8GB Ram.  The projects I create are on average 2 hours long, and I produce about 160 of them a year.
I've exhausted trying to find answers on the dicussion forums and online and I can't figure this out.  I'm probably an idiot overlooking something, so I'm here seeking guidance.
I finally completely dived into FCX this past month after all the great updates.  I LOVE the program.  There's been some growing pains getting myself up and running, but I'm pretty much to the point where my workflow is becoming second nature like it was in FC7. 
But, Compressor 4 is leaving me stumped.  Here's my issue.  If I take a master H.264 file that I produced from FCP (7 or X, doesn't matter), that's between 8-10GB's in size and put it in Compressor 3, not changing anything about it's native settings or anything with Q-Master and/or clusters (picture installing it, then instantly create a DVD image file from a master H.264... not touching any preferences), it'll shoot out a disk image file in about 2 hours for me.  A Bluray image in maybe 3-4 hours. 
This all using i7 quad-core processors in iMacs. 
If I try to do the same in Compressor 4, it might take 4-6 hours to produce a DVD image file.  6-8 hours for a Bluray image file.
This isn't isolated to one computer, but on any computer I try.  It's PAINFULLY slow.  Being 64bit, I was expecting it to be twice as fast as C3. 
Then I got into clustering and Q-master and all of that.  I've spent days trying to get it right with a lot of trial and error.  But whenever I create a cluster following tips on these very forums and others that match the specs of my machines, there will be no dramatic increase in these speeds and most of the time I'll get some crazy number like 36 hours to process.  In which case I turn the virtual cluster off and have to settle for the usual 4-8 hour timeframes for it to spit out files (whether they be DVD files for Bluray).
Can somebody with extensive knowledge of C4 please tell me why it's not fater than C3 (I'd be happy with equal results) and what, if anything, I'm doing wrong. 
If it helps, one of the computers I'm using is an iMac quad core i7, 2.93ghz, 8GB ram.  Just want to throw that out there so if anyone wants to offer "step-by-step" instructions on how to maximize the power of C4 for me on one computer (not interested in daisychaining imacs, yet), they have the vitals for one of my computers that I'll apply those settings to and hopefully figure this thing out.
Thanks to any help or advice in advance!!

Answer 1

Hi David,
Thanks again for your taking the time to investiage some of this stuff for me.  I never would have thought to even try a ProRes file, so you learn something new everyday.  After your tests and results above, I decided to do some tests of my own.  I took 35 seconds of raw footage from FCX and exported using "Master File" and changing the settings to 'LT'.  The resulting file was 490 mb's in size, but only took about 6 seconds to export (impressive).  I then tried the m4v 1080p route.  The resulting file was 44.9 mb's in size, but took a little under real time (about 32 seconds) to export.  Both videos look exactly the same when played back in QT.
I then dumped both in Compressor 4 and had the same results you had.  The m4v took twice as long as the LT file to export to DVD (one pass) and four times as long in two pass mode. 
The next thing I'm going to do is burn a couple test DVD's, one with one pass and one two pass and see if there's any difference in quality.  I've been exporting as two pass and if one pass is twice as fast, I'd be extremely happy with that.
As must as I'd like to go the Pro Res LT route for faster Compressor exports, the resulting master file sizes would be way too big for me.  I tested a two hour long video and according to FCPX estimates (I didn't actually export the video in this case... just going by what the program is estimating), a Pro Res LT file would be 96.7 GB's in size vs. 8.87 GB's for an m4v file.
Since I include the m4v files as part of the package I return to the client so they can play them in iTunes or Quicktime, on top of DVD's, even if I used the ProRes master file I'd still have to produce an m4v from that.
So for my workflow and for storage reasons, I'll probably stick to creating m4v files as masters since I see no difference in quality.  I'll just have to live with the time it takes to produce the DVD's, but if I'm able to get away with 1 pass vs. 2 pass, that would dramatically speed things up.
So you've helped me on two fronts Dave... one with the number of instances for the clusters, which has worked wonders on real projects here for me the past couple of days (and going forward), and the second with the insight about ProRes files, which led me to determining if one pass or two really makes a difference when exporting m4v files.
Thanks again!