2 ) I'll be getting a new Mac Studio to replace my 2009 Mac Pro with four 3.5" 6Tb internal hard drives. Is Thunderbolt data transfer faster than my 2009 5,1 Mac Pro internal hard drive connections?
Thanks !
The simple answer is NO. You are limited by the transfer rate of the hard drive itself. Hard drives don't even come close to the rate USB3 can transfer. You have to be using SSD's and NVMe drives to approach the speed thunderbolt can transfer.
Here are some sample speeds from my own test using my 2012 MacBook Pro (internal SATA3, USB3, Thunderbolt 1 and a friends MBP that has TB2):
------------------------------------------------------------write mb/s-------read mb/s
Internal 2.5 inch hard drive via SATA3 (2012 MBP)--------96--------------102
2TB Hitachi 7200rpm dive via USB3 dock------------------134-------------146
2 - 2TB Seagate hard drives in striped raid USB3 dock----377-------------390
Samsung 2.5 inch SSD via SATA3 (2012 MBP)-------------483-------------505
4 - 500gb Crucial SSD's striped raid via Thunderbolt 1----755-------------810 (seems to be the limit for Thunderbolt 1)
4 - 500gb Crucial SSD's striped raid via Thunderbolt 2----984------------1181
NVMe drives are in the 3000 mb/s + realm. They are more expensive, can get hot (and may throttle their speed because of high temps. You will need Thunderbolt 4 to take advantage of that speed.