iMac slow to boot up - maybe the fusion drive?

I've tried pretty much everything to speed up my iMac (all the usual top reasons). No success. I now suspect it's an issue with the fusion drive. I've attached an image - and the overview the computer. Can anybody tell me, does the fusion drive partition hierarchy look correct to you?

When we first bought this iMac, we wiped it clean and reinstalled a previous (Mavericks) OS, so as to run certain software. Did something go wrong? Seriously, it takes more than 5 minutes to login and get to a ready state....

Thnx for any help