How to avoid sluggish UI in FCPX - more CPU, GPU, RAM or what? My question is about what aspects of hardware performance would best prevent sluggish UI and 'beachballing' in FCPX.

Currently I am running on a Macbook Air Core i7 2.0ghz, 8GB RAM and Intel HD4000 graphics.

I am editing 1080p only. The project files are on a Drobo 5D raid-style Thunderbolt drive connected via Caldigit Thunderbolt dock.

Generally the edits are not complicated, just one layer of video with some colour correction basic filter and transitions.

I realise my current system is underpowered, and at times I suffer from unresponsive UI. My question is what upgrade would give the most benefit:


quad core i7?  (currently dual core)
16GB RAM or more?
discrete GPU?  or more recent Intel Iris would be enough?
if GPU, is available video RAM more important than processing power?
the current HDD should be fast enough?


I want to stress that, for the purposes of this question, I do not care about rendering times - only to avoid unresponsive UI.

I have proxy and optimised media for all my projects, and I have the proxy media playback option selected:
Your hardware is NOT underpowered. I can run FCPX on a old MacBook Air using proxy media, with only 4GB if memory. That machine is much slower than yours. So it's not the MacBook that's the problem.

Have you tried to copy your media to a local drive just to see if you have issues with your raid system?

Another thing to check is running the Activity Monitor utility and see if your CPU is busy when you get the beach ball. 

Before we know why you are having these issues it's hard to give a recommendation on what parts to upgrade.