I have a maxed-out iMac, but FCPX is still slow.

60watt,

You have not supplied much information so we really cannot tell what the issue is. First, I'd recommend posting in the FCPX forum located at Final Cut Pro X and while doing so you may want to post an EtreCheck report of your system. This report can tell others how your system is configured and point out any obvious red flags.

60watt wrote:

or is truly, this cadillac of iMacs just not powerful enough to handle this kind of rendering? I'd love an opinion if you've got it!

iMac (Retina 5K, 27-inch, Late 2014)

4 GHz Intel Core i7

32 GB 1600 MHz DDR3

AMD Radeon R9 M295X 4096 MB

Well Alex Lindsay, founder and CEO of Pixelcorps and former Lucasfilm member who worked on the Star Wars movies says, Pixelcorps uses 5K Retina iMacs for most of their production work, not Mac Pros. Having recently filmed in the White House with President Obama Pixelcorps apparently thinks the Cadillac iMacs have plenty of horsepower for professional use. Maybe you could retain Pixelcorps as advisers on how to use FCPX on your iMac. They seem to know.

As raufkann87 suggested download and run Etrecheck. Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here (and recommended by Apple Support personnel) in the ASC to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

The Drobo is the problem, they are fine for backup purposes but they are not designed for or are any use for video editing.

No enlightened video editor would use a Drobo as a media drive. Buy another drive; Promise, G-Teck, Sonnet, LaCie

That report is for a MacBook Pro, not a maxed out iMac. Also you need to copy and paste the Etrecheck results into your thread, not post a screenshot. The info from Etrecheck goes much farther down in the report that the little bit shown in the screenshot.

I have the exact same setup and have no trouble in that respect, (Importing very Long Clips is another story) Run your activity Monitor and reboot FCPX when memory used approaches 20GB or reboot mac when Cache exceeds 12GB, if I exceed these limits things Start to Slow Down.

What drives are in your Drobo? How are they formatted? Are they set up as a RAID or some Drobo-specific arrangement?

I don't associate Drobo with video drives, but I am not too familiar with them.

You could run BlackMagic Disk Speed Test on the Drobo and tell us what you get.

Also, you could try creating a test library on your internal SSD and compare - it is likely to just "fly"...

A cheeky PRAM reset fixes some odd quirks.

Hold CMD + SHIFT + P + R at boot, wait for Apple logo and it will reboot the machine. Remove keyboard press. Basically flushes a cache.

I believe your key combo is off by one key = NOT SHIFT but rather Option

Resetting NVRAM (PRAM)

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R.
3. Turn on your Mac.
4. Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.
5. Hold these keys until the computer restarts and you hear the startup sound for a second time.
6. Release the keys.

How to Reset NVRAM on your Mac - Apple Support

Correct! My bad.