The footage is from the Sony NX3 and its horribly choppy when editing / playback on Premiere Pro 5.5.

Maybe I need a faster computer or more RAM? (I have the Intel 8400 and 4 gigs of RAM)

Convert it to another format?

Any help would be greatly appreciated. Right now, as I go through the editing, about every 5 seconds it becomes too choppy when I am playing back on the timeline.

Thanks!!

I have an i7-4770, not the fastest or greatest available but with 16 Gb RAM and a 1 Gb graphics card on board it runs anything i've had to edit so far!
Haven't tried any 4K stuff yet tho!

I'd imagine 4 Gb of RAM is not enough, also you don't say if you've got a dedicated graphics card or not?
but maybe a new system with plenty of RAM and a good graphics card is the solution, especially for AVCHD

That CPU is way underpowered to handle AVCHD footage. It is 6 years old and has only 2 cores. In addition 4 GB is not enough by far. Time to upgrade...

For ideas, look at What kind of PC to use? (http://ppbm7.com/index.php/tweakers-page/87-what-pc-to-use/98-what-pc-to-use)

Silas,

The only thing that will help your AVCHD editing performance, as Harm stated, would be to get yourself an entirely new computer system. This is because any upgrades to that old dual-core system would cost you much more money than the performance benefit justifies; in fact, you could spend thousands, if not tens of thousands, of dollars on that old rig and its overall performance would still be significantly slower than even a cheapo modern Intel i3-powered beginners system.

In other words, don't spend a dime for incremental upgrades on that old LGA 775 rig. Even a $10 upgrade would go to waste.

Bite the bullet and pick up an I7 with at least 12 gb of RAM. You'll be glad you did. Adobe has made massive strides in performance with the 2014 cc updates. You can have it all for $50 a month but it probably won't help your current plight.