Yes, with Sunshine disabled speed is normal.
I have the same problem but making the suggested change did not improve things.
In fact ALL admin activity is very slow with Sunshine active – for example it takes 18 secongs to show All Pages, and then the same again to open a specific page.
And loading pictures to a new gallery was taking 10 seconds an image – although the images were put through JPEGMini before loading.
This is a new installation of Sunshine and there are 3 galleries up at the moment with around 3000 images. I do hope that this can be resolved as admin work on our website is currently very time consuming.
