The 60i setting should work best with PRE with the Full HD 1080i preset.
As for performance that can be highly dependant on your system and how it is set up. By default most PC's startup with a whole load of cr*p provided by your supplier - all of which can eat into your performance. Anti-Virus software (especially McAfee) can cripple PRE. Try working through the steps in this article: PrE Hanging, or Crashing - Some Tips. If that doesn't solve your issue then this article lists the things we need to know about your system and clips - Got a Problem? How to Get Started
Insanity is hereditary, you get it from your children
There is a minefield of ifs and buts in video editing
I find that the quality of the video card in your computer affects these combing effects etc more than anything else - but not always.
I have three computers with different setups and they all play the same video differently.Laptops and video on the motherboard generally are pretty hopeless.
If you start with a perfectly good full AVCHD, make a lower definition FLV with PE9 and export it to Youtube it definitely shows interlace jagged lines on rapidly moving objects.
If you make a M2ts from it on a Blue Ray disk it its perfect.
Other reports say if you make (share) it as a WMV and send it to Youtube and they make the FLV then it is better!
Incidently full 1900 x 1080i AVCHD previews and plays perfectly smoothly on even an old 2.4g duo core computer with 3g RAM without any jumpiness or visible artifacts with a medium speed video card as long as:-
1.You render the area you want to preview (no red line above the timeline)
2. have the video files on a different hard disk to the project files, (preferably 3 disks. C=PE9,.E=Video, F=Project)
3. have all possible other memory resident programs or utilities definitely closed.
It only takes a few seconds to start preview of anwhere in a 1 hour video if you turn off the timeline thumbnails until you really need them.