partitioning your system drive MAY OR MAY NOT be enough for you to get good audio recording performance using the second partition of the drive. as said before, there is still only one drive which will have to do the recording at the same time as it does the system work. however, in theory, protools will not require much data throughput but needs fast seek times, so it MIGHT WORK very well if you optimize the seeking with your partitioning scheme. as you know, not all areas of the hard drive are made equal - disk is round, and therefore area on the outer edge of the disk is faster than area closer to the center; and for the same reason one gigabyte on the outer edge takes less sectors than one gigabyte closer to the center, and therefore seek times are a lot faster on the outer edge. this is a physical fact. to make that fact work FOR you and not against, you need to partition your drive; first you put in the system partition, as access to it must be lightning fast - do not make it any larger as it needs to be (!) so take 10-12GB for it, or 15GB if you know that you'd be using some really big apps like final cut pro. THEN, estimate what is the longest single session you are working with, and double that. calculate the required storage space for that session length with maximum track count (32) and your typical session parameters (24bit/44.1kHz?). then add 15% and there's the size for your WORK partition, which should really be much less than 50GB. after you have created the SYSTEM and WORK partitions, leave the rest for USERS partition, where you store everything else except the system files (+apps) and the current audio session you are working with. (as a side note, you will have to edit /etc/fstab file to make the USERS partition to mount to /Users so your user files and preferences are not stored to the system partition. i will help you with that if you cannot find the threads where this has been discussed before.) now if you have such partitioning as i described (SYSTEM,WORK,USERS) you should in theory be able to use your work partition even if it's a system drive. that is because doing what i told you the seek times have been optimized and LIKELY (not a sure thing, but a strong possibility) the seek times are fast enough even if the system must seek something while you record/playback in protools. godspeed!