Interesting I'm sure I saw around 500 MB/s on my 4TB EVO drives. I will test again tomorrow.
One thing i did was move a lot of games from my EVO 870 SSD to my 990 PRO (7000+ MB/s) which is in slot 1cand didn't notice any quicker load times.
I get over 400 MB/s for my 2TB 870 EVO on SATA, the way I've my games sorted is older games on the 970 EVO or mechancial drives and most modern games on my 2TB NVMe 980 Pro, the Samsung portable T7 SSD in USB C connected I use for any game, don't notice any real difference to be honest in gaming, maybe my 64GB ram helps.
There are plenty of older games that are more then fast enough on SATA SSD, I even tried USB 3 on mechanical drives for older games with no issues. I actually tried "No Mans Sky" on my 980 Pro NVMe and Samsung portable T7 (USB C mode), no difference in gaming. Yes 980 Pro is a lot faster on paper and hardware wise, but does not mean you will actually feel or see the difference in all games.
Anyway newest games I stick on the Samsung 980 PRO , speedwise 6928MB/s. Older games I play like Baldur's Gate 1 or 2 Enhanced are more then fine on my Samsung 870 EVO or even mechanical drives.
There are some benefits to having games or files on diifferent drives ie less wear and tear compared to everything on one drive.
Also in the older days you had a physical copy of the games ie floppy, CD or DVD, nowadays it's all digital downloads.
I must be one of the few with both USB floppy and USB DVD drives
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