I got a Precision 7750 last week and have spent the past few days trying to get it working correctly. It came with Windows 10 installed, but I replaced this with Ubuntu 20.04 LTS. 

Unfortunately, Dell would not provide me with a copy of the Ubuntu OS that includes their own drivers and tweaks, so I had to use the vanilla one. On BIOS v 1.4 the battery would not charge. I've now updated to BIOS 1.5 and performance has become extremely sluggish. The trackpad buttons don't work. 

To test this, I ran the Geekbench 5 benchmark and obtained a single core score of just 259 and a multi core score of just 1595. 

https://browser.geekbench.com/v5/cpu/5175065

Other Precision 7750 machines are typically getting single core scores of 1300-1400 and multi core scores of 6000-7000, so something is massively wrong somewhere. 

https://browser.geekbench.com/v5/cpu/5161262

The top command shows there are no processes using up lots of memory or CPU, so I'm stumped at what may have caused this. Does anyone have any ideas, please?