newbie non urgent help needed

Hi I am an experienced linear and non-linear editor (20yrs) but new to FCP.
I have a system set up at home that I am just messing around learning with and have had a couple of problems.
I have a dual 2.7 G5 with 4GB ram. I am using FCP Studio V5.04 OSX V 10.44 and QT V 7.04. I have a 2nd internal 250GB SATA hard drive and a Lacie Firewire 800 HD for media.
I digitised some media at work from digbeta 10bit SD and have copied the media to the internal SATA drive.
I was editing a simple video only sequence of around a min all was fine till I added a dissolve and a slomo clip.
These were rendered to the SATA drive and now my timeline keeps dropping frames and wont play. If I remove the effects clips the sequence still wont play without dropping frames.
Other much more complex sequences in the same project, all cuts but - 7 video layers, captions, mattes fills etc using the same media on the same drives work fine.
Has my sequence become corrupt in some way ?

Another thing was I added a dissolve to a rendered clip (tga file) then removed the dissolve. The section that was in the dissolve then became unrendered. Is his normal ?

I know this dropped frame thing has been gone over again and again but as far as I can see my settings are OK.
What might I have missed ?

Thanks

Neil

You are trying to do 10 bit SD on a single internal drive - That is the problem.

You need some sort of RAID that will give you enough bandwidth for at least 2-3 streams of SD to insure no drive read issues. 10 bit SD is around 25 MB/sec per stream. so at least two SATA drives with a RAID 0 setup would allow for at least 3 streams and 70 MB/sec.

Hi John

thanks for the reply - I realise that using this media on an internal drive is pushing my luck speedwise. I was kind of suprised when it played perfectly.
As I said the same media plays fine in a different 7 layer sequence with titles and mattes so was a little suprised when a simple dissolve and slomo made it fall over and removing the offending items made no difference.
I'll find some lower res stuff to mess with.

Neil,

One SATA drive on the internal 1.5Gbps bus can do around 45 MB/sec which can transfer one stream of SD 10 bit. My recommendation is based on experience and the SATA RAID solution is very inexpensive. Formerly, a SCSI RAID was the only solution.

John

thanks again, if I need to work on this system for real then I will take your advice and go the SATA RAID route. I am messing around learning the software and in this instance only playing a single stream, its about 8 cuts amounting to less than 30 secs. Since the much more complex sequence was ok I thought that perhaps drive speed was not the issue and I needed to look elsewhere.