In short, you need multiple disk setup so as to eliminate reading/writing at the same time conflicts. See this Optimizing Hard Disks video from Todd. The video contains the reference to this Harm's article about disk setup.
Also your laptop amount of RAM is far below of what you need for good performance. A practical minimum is 8-12 Gb (and 24 Gb or higher - for optimal performance).
Moved to hardware forum
Rex, the three disk setup is a good setup but for a laptop like yours with an external RAID 0 setup, it is quite adequate for medium compexity codecs like AVCHD if you are getting good performance from the RAID 0 system because a two disk RAID 0 system should be almost double the read and write times which makes it possibly even better than two seperate drives
Yes you definitely will be better off with more RAM.
I am editing AVCHD on a Sony laptop with a very similar spec to yours, with media on an external eSATA drive which is not RAID.
BUT I replaced the supplied 5400 rpm drive with a 7900 rpm Seagate Momentus XT, and added another 4GB of RAM. This is the laptop's limit for RAM, but I wish I could add more. I have 32GB in my desktop.
Thank you all for your helpful advice, Fuzzys post in particular proved very helpful, the video and link provided everything i needed to know, and as a result of all your input i have now decided to increase my Laptop ram to the system maximum of 8GB, and have also ordered an additional esata external Black caviar 7200 hard drive to store my Render/Scratch files..
Thanks a million guys.
All the best.
In the end, it is about spreading the I/O load over more HDD's and controllers. That way, nothing is waiting on anything else, to complete its tasks.
Can one work with externals, with fast connections? Absolutely.
Though I have 3x internal SATA II's on my laptop, I need to migrate many of my Projects between computers, so I give up some performance by NOT spreading that I/O load, but it keeps my Projects, Media and Scratch Disks on one FW-800 external. Not ideal from a performance point, but adequate for me in most cases. A compromise on throughput makes life easier in other respects - at least for me.
Good luck, and that link that Fuzzy provided IS a good one.