Logic Pro 7 & earlier Logic 7.2, EWOLSO, MacBook, Play


Need some advice. Just got East-West Quantum Leap Symphony Orchestra, Gold Edition. Love the sounds on there. some amazing stuff. Trying to put a piece together now but..... boy is my machine getting fried.

right now i have five audio instrument tracks using EastWest's Play AU function :

track 1: flutes in the upper register, clarinet in the lower register
track 2 : pizzicato ensemble (3 instruments together)
track 3 : percussion (slap sticks, cymbal)
track 4: various percussion ensemble
track 5: celesta & glockenspiel

sometimes I can get all the tracks to play together without the program stopping and giving me a "Logic had an error synchronizing Audio and MIDI" or whatever. freezing the tracks sort of helps. but sometimes i cannot even get one track to play past a certain point. i start getting digital clipping. it is driving me nuts. i am wondering -- do i just need to give up on trying to use this big of a program until I have a better computer (i.e., a desktop) ?

Not sure if the drive I'm trying to stream the samples off of is not good enough or what -- I'm using an eSATA drive through a PCI card slot. Here;s the details of what I'm working off of :

Logic 7.2 (academic), 15 inch Macbook, 1.83 GHz Intel Core Duo with 2 GHz DDR2 SDRAM.
samples streaming off of a 750 GB Seagate external drive via eSATA card in PCI slot. been experimenting with streaming some of the samples from the disk and loading other samples into the Macbook's HD cache (Play has an option to "Stream from Disk" or not.....) ..... so far the best option has been to stream the biggest samples from disk, and not stream the ones that are smaller (the percussion).

Any advice beyond "get another computer" would be much appreciated..... thanks so much!!