are you sure it's not because you have smooth-scroll enabled?
If you spend a bit of time exploring the extension's options you should be able to find a combination that hits your personal 'sweet spot'. I've also found that really dialing in consistent smooth scrolling performance can require optimizing other factors including: OS settings, mouse software driver settings (I use Logitech Options), video card options (VSync especially) and even monitor options (often disabling motion 'enhancement' modes) because the end result is only as good as the whole stack.
It can help to ensure your hardware has sufficient performance to maintain your desired scrolling performance even when multi-tasking and the browser loading website with a bunch of JS and assets, especially on laptops and wireless connections. UMatrix helps block a lot of these loads.
If you have intermittent variable results, another thing to check is other FF extensions. I run quite a few extensions to customize my experience and have run across a couple (unrelated to scrolling, screen or visual appearance) that make scrolling performance on some sites inconsistent during background page load, perhaps some rare interaction of threads. Fortunately, none of them were any of the popular ones or ones I find essential.
I don't think it's possible to achieve truly 'perfect' scrolling behavior 100% of the time on all sites yet, at least I haven't been able to on any desktop browser or hardware combo I've tried. Currently, I'm quite happy with my FF configuration as all the sites I visit regularly perform very well and >95% of one-off sites do also.
I don't know what changed, but I haven't looked back.
What platform do you use?
I think if you can keep the mouse off the page and on the scrollbar at the side (I'm on mac) it scrolls more predicably.
Wheel scrolling is awful in all browsers. The way to scroll is to use middle mouse button and move the pointer.
Only doing this you can accurately judge scrolling performance. I don't want 'snappy'. I want smooth.
Tried everything, even resetting the OS.
Have a new MPB since Monday, tried Firefox again, no issues at all.
general.smoothScroll.msdPhysics.enabled
to true (by double-clicking).EDIT: Formatting.
mousewheel.acceleration.start mousewheel.acceleration.factor
I have them set to 1 and 15.
Works with Thunderbird as well!