Where is the bottleneck?
 

Hello,

My Setup:

Macbook Pro 17" Duo 2 Core 2.5Ghz \ 4GB Ram \ GeForce 8600M GT 512mb / 200GB 7.2k HD

Software: Final Cut Pro 6.0.5

Footage: 2x Streams of AVCHD transcoded to Pro Res 422 (in FCP) 1920 x 1080 29.97fps.

I'm watching the edited multicam sequence in FCP in a small window. The preview is set to draft. RT set to unlimited. And my macbook just can't play it back smoothly!

I've tried restarting and FCP is the only program running.

Suggestions?

Idea
 

What about playing the footage from an external FW800 drive with plenty of room?

Sounds like your bottle neck is indeed the harddrive/codec issue. You're trying to pull 35+MBytes per second from 2 different areas of the disc (2 media files) from a system drive. Sounds like a recipe for failure in a laptop to me.

I third the suggestion to transfer the footage to an external FireWire800 drive. This is just too much for the internal drive to deal with.

Yeah the 1Gb per minute of Pro Res 422 is quite nasty.

I'm going to run a benchmark on my HD to see what I could possibly pull of it.

I actually don't own a Firewire HD so I'll need to get one in order to test that out. Makes sense to me though.

I hear xbench isn't very reliable...

http://img.skitch.com/20090411-rj9kb...r1n7sump4m.jpg

I checked the activity graph and it showed a peak of 30.65MB/s after playing the multi-clip sequence.

EDIT: I tried putting one of the files on a external USB drive. It plays back smoothly. The HD is definitely the bottleneck.

First, is the sequence fully rendered?

You can't expect high-performance real-time playback from any MBP most especially from the single internal HDD, there just isn't enough data-pipeline available on the mainboard.

An external drive would help substantially but it would need to be eSATA connected via the ExpressCard adapter for there to be a real benefit. FW800 doesn't have enough bandwidth to support multiple-stream HD playback however a fully-rendered sequence will have an 80% chance of getting smooth playback with the sequence settings you're using.