Sql server ssd slow performance

Whenever you've got a performance problem, start by asking, "What's my top wait type?" Wait stats tell you what SQL Server is waiting on.

I like measuring waits with sp_BlitzFirst (disclaimer: I wrote it.) It's a free, open source, MIT licensed script that you can call to take a sample of your waits, like this:

EXEC sp_BlitzFirst @Seconds = 60, @ExpertMode = 1;

That'll take a 60-second sample of your waits. Post a screenshot of the wait stats section, and we may be able to explain what the server is waiting on.

Update: your added screenshot shows 2 seconds of WRITELOG waits in the span of 60 seconds. Basically, your SQL Server just isn't waiting that much. My guess is that your simulated workload involves serial singleton activity: working on one row at a time, from just one thread in a load generation tool. That's not a great way to simulate workloads - you'll want to use a multi-threaded load generation tool, with lots of activity happening at once, and doing more than one row of activity at a time.

Okay, I solved it. After searching around and trying lots of different stuff it finally came to an end.

I wrote in the original question that "all my drivers are up to date", which, looks like it was a jerk lie coming from me. I apologize for that, I updated only the firmware and had visions of updating the driver as well.

Seems like everything was solved by installing the latest driver from the original site of Samsung. IMHO I didn't expect such drastic changes over a driver change.

The driver I had before was, as shown in the tool "Samsung Magician" under the NVMe Driver, owned by Microsoft. After installing the Driver, it shows Samsung.

I again apologize for the misinformation, and I thank Brent Ozar for the support, which without, I would've long abandoned this quest and would've just "dealt with it".