You'll have to find what's different from their to your PC. You only noted dollars but no hardware.
Read https://www.reddit.com/r/PCMasterRace/wiki/builds where 800 dollars can go quite high end.
For me to see what you have, supply the PSU make and model then a WEB SPECCY report at https://www.piriform.com/docs/speccy/using-speccy/publishing-a-speccy-profile-to-the-web
recently I watched a video where they tested sues shaders ultra on a 500$ pc and it ran with 60-70 fps, but I have a 800$ pc and I ran the same sues sharers ultra with a 8 chunk render distance and I got no more than 20 fps!! plz help!

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