Same here, sad part is I contacted Evernote support, send them screen videos etc, they said we couldn't reproduce this issue. After 7.8 update they send me an update mail that in 7.8 version this problem is gone :)
I updated EN and I tried, some pdf's scrolling a bit better but app's general performance is not good enough. I have notes which has maybe 30-35 attachments (word, excel files), scrolling performance terrible.
I tried BEAR app for a while, its performance is amazing. Buttery smooth scrolling and writing experience. Maybe one or two extra functions keep me using EN.
I'm using EN with MacBook Pro 2017 i7 16Gb Ram 4Gb Radeon 560 512SSD.