Well Mark, here's the deal.
To start with... on page 1 of this post, you'll find a great comparison/contrast of FCP, Avid and Premeire.
However, to answer your question in short... Yes or Yes and Yes.
For one, all professional editing software will have longer rendering times... because they deliver professional quality performances, and that just takes some time... the more ram you have, and the fater processor... the less time it'll take.
Secondly, Avid and FCP are both much more efficient that Premeire. The Adobe line of products (ie: premeire, after effects, etc.) have always been ram-hogs. Meaning, that their render time, and the amount of work they make the computer do... does not equate to the quality of product they present in the end.
Also, Avid and FCP are both much faster in many ways... in comparison to Premeire. For the same reason as above... and basically it just comes down to two major reasons why Premeire isn't up-to-par with FCP and Avid.
#1 - Premeire is not a true "Professional" editing system. While it does have many professional uses, and is used to varying degrees in various parts of the industry... Premeire can best be described as a semi-pro software. It still has many of the qualities, including visual image quality, that consumer level programs generate... as well, it has some professional options; like multiple video and audio tracks that can be expanded for more options & some limited compositing.
#2 - Premeire is just not programed as well as FCP and Avid. This is most evident in the over-all end-product visual quality. I can watch a thousand videos, and if only ten in that thousand are edited with premeire, it will be quickly evident. There is just a certain way that premeire treats visual images... and it's almost like it's stamped a logo on the image... it just isn't good enough for the highest end application (like film editing). Also, the way it abuses the processing power of your computer... hoging all of the system resources, and abusing your RAM... Premeire is just not up to the task of competing with FCP and Avid. Premeire Pro is a program that is meant to compete with FCP 4.5 HD, and Avid Express Pro... but in reality, it's more comparable to FCP-Express, and Avid Express DV.
If you have the money, I would seriously suggest investing in either an Avid Express or a Final Cut Pro program... even the lower end versions of this software are much more efficient thatn Premiere.
If you're on a PC, definetly go for an Avid system...
if you're on a Mac, then it's up to you... try to find somewhere (like an Avid Reseller who also deals in FCP... common occurance) where you can demo both products... find the one that has the best editing work-flow for yourself.
Visit the avid website, and search for a local re-seller near you... then juts contact them... they'll sell to anyone, and usually they're not interested in pushing a product on someone that they wont want or need... they just love to demo the products, and sell what will work best financially and artistically for the client.
Good luck, and happy editing!