FCPx and the Mac Pro

I've asked this before, but I'll try again. I got a pretty high-end Mac Pro over a year and a half ago so I would have the "perfect" FCP editing system. I thought the two products were supposed to have been made for each other. I have a couple of 4TB thunderbolt G-Raids and some single G-drives. I shoot various formats but always optimize to ProRes. Here's the thing. The system as NEVER - N E V E R worked really well. I've always been disappointed in the performance, even for what would seem to be simple projects. I get hesitation before playback. Occasional beachballs. Hesitation when dragging a clip to the storyline. Real slow-up when added text tilting or, god forbid, a third-party plug in from FX factory or the like. It's been such a disappointment to spend over $7,000 for what I thought would be the top of the line Mac editing system, and it just isn't.

Is there something I'm missing? Do I NEED to spend $3000 on a big raid system? The G drives and Raids promote 165 MB/s or even more and ProRes is like 17 MB/s? It's not like I'm layering 7 video tracks. Just simple timelines are a problem. And the rendering seems to take forever, all the while the placed dissolves or transitions stutter along.

It seems like with all this promoted "macPro power" I wouldn't need to edit everything in proxy mode.

Our iMacs do just as well as the MacPro.

Am I the only one disappointed in the promises of this computer?

So... any ideas? Suggestions?