Interestingly (and probably many already know this) but the arp or sync works much better with patches with LOW complexity (as stated by the indicator on the LED screen)
I was just playing around with a very simple saw wave patch with and without unison, nothing else (seemingly) enabled or going on. With unison it just stutered and was awful, but was okay without unison (doing a classic standard 16ths trance riff)
Noticed the meter was high for complexity (even though just one osc and nothing else enabled) so went to an INIT patch and recreated the same lead sound,. VERY low on the meter and syncs fine, no dropouts, no missed notes. But the patch is basically exaclty the same sound but clearlt internally different, with less enabled ( perhaps not turned off)