Not sure I can answer this max - the current Cubase manual is not very forthcoming (see around page 23-4)
Under Devices>Device Setup>VST Audio System I have Audio Priority set to Boost. Other settings here are default
Disc pre-load 2 sec
I usually run at a latency of 256 for recording multitrack audio, sometimes 512. Of course it will run much lower if needed (eg playing a VSTi) but no point in stressing the CPU if you’re recording a lot of tracks.
For the record I just set up an empty project in C6, 24 STEREO tracks at 44.1k 24bit. It’s recording on all tracks as I type this… at a latency of 192 on the internal soundcard cpu and disc activity barely twitching.
OK, I created another 24 stereo tracks, and recorded on them whilst playing back the first 24 tracks. No drama.
This is on the internal HD, which as I say is the optional 7200 rpm drive. My MBP is an early unibody, late 2008, 2.53 gig Duo.
Assuming your MBP is on OSX, not bootcamped. BTW If you’re not running OSX.6 Snow Leopard you are missing out on quite a lot of performance - OSX.5 Leopard was much slower for Cubase.
Do you have plenty of spare capacity on your system drive? OSX doesn’t run well if your system drive is nearly full.
If you’re still having this issue, I would re-install Cubase. Also check you have the latest RME drivers and Firmware.
Finally, there was an issue a while back with certain Mac laptops and the Firewire controller chip - it didn’t play well with FF400s. I’m not sure if the issue was ever fixed but suggest you check the RME forum.
Maybe eliminate the RME by recording a multitrack test with the internal soundcard set in Devices.