Whenever I run into FPS issues, I immediately go into my Windows settings to make sure nothing there has changed. Head over to Windows "Power Options" and ensure that you have "max performance" selected. Also check in your Nvidia (or other GPU settings) to make sure your graphics drivers are up to date, and that you have the proper settings enabled for Destiny 2 in order to garner the most FPS possible. If, in the past, you have gotten 60+ fps with certain settings make sure those settings are exactly the way they have been when you go back to Destiny 2 to make sure you're hitting the frames you usually get. If not, just turn everything to low with FXAA x2 being the maximum. As a last resort, you can opt to turn down the render scale to 75 instead of 100. Makes everything look really trashy but significantly improves your FPS. If NONE of this works, you could perhaps be experiencing a hardware issue. In video settings, at the top, make sure you're not hitting the GPU cap as this can cause performance issues. If the cap is fine and you're well within the capabilities of your graphics card, then it could be a CPU issue...the most often of which is cooling. There are many ways to fix cooling issues but Destiny's fps is highly based off cpu performance. Over heating, not enough air flow, thermal compound issue, etc. are common causes of under performing CPU's. I'd actually like to know the specs of your computer to better assist. Cheers, and I hope at least some of this information can help clear up your FPS issues. Must be my least favorite thing to deal with. EDIT: Most important thing! You can actually cap your FPS within the destiny video settings....make sure you didn't actually misclick and add a 40 fps cap. Make sure it's in sync with the capabilities of your monitor or more.