Thank you for the quick reply. I am indeed using the beta and I am now running 10.10.3 beta (I apologies for leaving the OS info out). I downloaded the latest as you suggested. The performance is indeed much better but it is still not close to the 60fps that you are advertising and that I have seen in posted videos. There are still hitches during the pan and (occasional) zoom. The fps for panning is still low - I would say in the neighbourhood of 10-15fps.
I have been trying Affinity Designer for about 5 months off and on. I have a Mid-2010 27' 2.93 Core i7 iMac with 12 GB of RAM. I have been using Adobe Illustrator since 1993 and I find your app to be great in every way except in one of the main areas that you tout... Pan and Zoom. For me the performance of panning and zooming has been very laggy - no where near 60fps but more like 5-10fps. I have played around with the performance settings and have re-installed but nothing seems to make any kind of difference. I seem to be in a minority here so any help on this would be appreciated. I woul