Created attachment 8860704 [details] about-support-intel.txt User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:54.0) Gecko/20100101 Firefox/54.0 Build ID: 20170419004020 Steps to reproduce: My hardware: Dell XPS 15 9560, Resolution: 2840x2160 (4k screen), Intel Graphics HD 630. Display scaling: 225% I have included my about:support page as an attachment. Note that I plan to return this laptop within the next few days so I'm unable to provide more information. This laptop is fairly common so there should be other people who can further provide more information. Steps to reproduce: 1. Ensure that both Chrome and Firefox are using the integrated graphics, by checking it under the NVIDIA Control Panel (this is already the default behavior) 2. Ensure that Chrome is closed. Open Firefox, ensure it is maximized (important). 3. Go to a website with lots of content to scroll, such as http://reddit.com or https://news.ycombinator.com/ 4. Scroll up and down, you should see that scrolling is smooth. 5. Open Chrome, navigate to a fairly resource-intensive website, such as: https://www.apple.com/ca/macbook-pro/ 6. With Chrome still open, go back to Firefox. 7. Ensure that Firefox window is maximized, scroll up and down. You should see that scrolling is janky. 8. Resize Firefox window to about half to a quarter of the screen, scroll up and down. You should see that scrolling is smooth. Actual results: 1. Without Chrome open, and Firefox maximized, scrolling in Firefox is smooth. *[A] 2. With Chrome open, and Firefox maximized, scrolling in Firefox is janky. 3. With Chrome open, and Firefox resized to about half to a quarter of the screen, scrolling in Firefox is smooth. *[A] - This is only partially true. Firefox does have significant scrolling performance issue on certain pages, even with Chrome closed. To see what I mean, do this: 1. Ensure that Chrome is closed and Firefox is maximized. 2. In Firefox, navigate to: http://larian.com/forums/ubbthreads.php?ubb=showflat&Number=580880&#Post580880 3. Notice that scrolling is janky in Firefox. 4. Open and maximize Chrome, navigate to the same webpage. Notice that scrolling is smooth. Expected results: With Chrome open, and Firefox maximized, scrolling in Firefox should be smooth.
Component: Untriaged → Panning and Zooming
Product: Firefox → Core
I'm not able to reproduce this but the hardware I have is different from what you have (in particular I don't have a 4k display). Tagging as P3 for now, we'll investigate as time permits.
Priority: -- → P3
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