lots of dropped frames, out of memory, FCP 7 crashing.

No replies to my last post. It can be disregarded as I'm hopefully moving in a clearer direction with this related one...

I’ve been working on a feature length documentary for a very long time now and've started to run into issues - lots of dropped frames, out of memory, FCP 7 crashing. Everything was working just fine until two weeks ago when trying to render a heavily-effected clip. When trying to diagnose the problem, a couple people suggested to me that the culprit is the system settings, which are as follows:

1440x1080, 23.98 fps, HD1080p24, 48 KHz, 32 bit Floating Point

They told me these are outdated, basically awful settings, and that I need to change all the settings of the project. I’m not wholly convinced this is the culprit, but, from what I gather, my sequence settings are in fact yucky and could eventually make this very large project untenable, and will be improved in several aspects by correcting them. Therefore I think it’s very good idea, if possible, to switch the settings, regardless of if it solves the original problem. The settings I’ve found to be more appropriate is the highly recommend ProRes422, and then HD 1440x1080 for both pixel aspect ratio and aspect ratio (are these good, healthy settings overall?). But when I cut and paste an old sequence into the new sequence, all the audio becomes firmly mixed, as several video clips play with the wrong IN and OUT points - basically it’s a nitemare mess. Considering there's dozens of very densely-edited long sequences, to sort out this mess with individual clips is daunting, and would be extremely time-consuming - as in months- and if I can avoid this in any way, I’d practically give the world for it. Now, when I change the original sequence’s settings to the new settings, everything is just fine, no-one gets hurt. So another question I have is: Is it okay to change the settings that-a-way? Is it the same difference? If so, that would make this project within a project soooo much easier. Any help is much appreciated - this project has basically stalled due to these issues. Thanks.

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