Part of the problem may well be your choice of Ext HD.. as the WD TB HD is actually quite slow... being designed more as a Raid backup system than an Audio streaming drive...
However, first of all, lets cover a couple of the basics...
Are you using it in a Raid configuration and if so, which?
Do you have any background apps running at the same time as Logic and if so, which? (Any Anti malware stuff for example?)
Have you established that this is a 'drive speed' issue or a CPU issue? A glance at the System Performance meter should help here. Is the project simply 14 stereo audio tracks, or are you running a boatload of software instruments as well (especially ones that might be CPU heavy, or that may stream samples from the external drive)?
Whilst it's generally not considered a good idea to run projects from the System drive, it would be useful to copy the project from your external drive to the Internal drive and try running it from there. This should help track down any drive speed issues.
HiI´m using the HDD in standard mode 2 disc solution(it´s mirrored to another two fw800discs..)
my bg-apps are dropbox
then i run a couple of kontakt libraries (with kontakt memory server) along with some exs-instruments and some other softsynths. all my libraries are on one of the discs on that thunderbolt-drive.
It is my Disc i/o that hits the roof.
I thought that thunderbolt would solve my problem, could it be a possibility to change discs in that WD chassi? It´s a hotswap kind of solution on that (thats why i bought it), or... could it be the built in system in that chassi that is the bottleneck??
It could be the drives inside the enclosure.. I do know the benchmarks for that WD TB are very slow compared to standard FW 7200 rpm drives... Like I said, it's not really designed to be used for streaming audio.. It's more for making backups/Data storage and so on...
The available TB bandwidth isn't really being exploited at all by that device i am afraid to say, It would only be of benefit if you had several other TB devices in the same chain.. Then the TB bandwidth would shine and you would notice a benefit for sure. It's worth noting that TB does not always equate to faster drives... More bandwidth yes and it can handle multiple faster drives like 7,200 and even 10,000 rpm ones... for example with ease.. but using a single 5400 rpm drive enclosure isn't really going to benefit from the extra TB connection/bandwidth at all... It would probably run just as fast on FW800 or even USB2 ports!
I should also say, that the other suggestions made in the thread.. are also quite valid possibilities as to the root/partial cause of your issues. It may not be the drives alone but other factors too.. working in tandem with the slower drives. So, i would also investigate both Pancenter's and CCT's suggestions/ideas first before considering updating your HDs.
My current i/o buffert is 256, i did try to increase it to 1024, but that didn´t change. the hdd-meter hits the top on the bar. I did try to freeze some of my tracks, but that didn´t change the issue a bit. the strangest thing is that i never encountered this before and im worried (read paranoid) that this is a kind of mountain lion-related issue.
Of course I will not neclect the problems mentioned above, but:
#1 A system like this should not behave like this. If you were talking about the entry
MacPro model and nothing but that, maybe. But just maybe.
#2 Whatever system you have, you will experience "system overloads" within the first or second
playback of a project you just opened. That´s part of the deal if you want to go Logic, using 3rd party stuff.
#3 After the "routine" system overloads, well, Logic is extremely effective, tons of plugins..tracks and instruments.
My experience--with NI, 64 buffer, 64 bit
For now this is the way Logic works and the way it has always worked regarding plugins and virtual instruments.
It's because Logic does not keep plugins active, like most, if not all other DAWS. Logic does not activate plugins or instruments until right before region containing data (either audio or MIDI) is about to play.
DAWS that keep instruments/effects active keep the data buffers full and current.
The upside for Logic is that's it's far more efficient than most other DAWS as plugins/instruments are not active unless they're being used... the downsides (and there are several) is that Logic is susceptible to overloads, missed data if your song starts on beat one, erratic looping, glitches... especially the first time through. As I understand it, this was a design decision made,long ago when Macs did not have a lot of power and the processor handled system graphics.
It hasn't help any that Apple has let the development of AU languish. VST has had two major upgrades and is far ahead of AU in specs and features.
If anyone wonders why Logic 10 is taking so long it has to be built from the ground up and it won't be this Logic anymore.
You can see Logic's "buffer behavior" in action by creating a project that puts a light or medium load on the system right at the beginning... at bar 30 on three tracks not previously used in the project create 3 new regions, one per track, load each of the three tracks up with a Space Designer and/or Sculpture, anything processor taxing. After the project has been created, close it. Open a few other projects, play them then go back to the test project.
Logic's CPU meters will not register the plugins/instruments at bar 30. (Most DAWS will have increased CPU activity) Play the project, as you approach bar 30 all three tracks/plugins/instruments will become active at once.. depending on the project you may see an overload. However 2nd time through the buffers will have data loaded.