Will using a sata1 drive as a system drive slow down a home NAS?

Question

Iron

There is a home server with the following configuration:
ASRock Rack E3C226D2I (6 x SATA3)
Intel Pentium G3420
2 X Seagate ST4000VN000 in a software raid (mirror) The
server was running FreeNAS, which was loaded from a flash drive. The speed of the system drive in this OS did not matter.
Decided to switch to Windows Server 2012 r2. I found an old laptop Seagate ST9250320AS with a sata1 interface and used it as a disk for the system.
The system boots very quickly, but there are some doubts.
I want to know from those who know whether the system disk will somehow limit the speed of the storage (mirror)? Is there any benefit from installing it as a system SSD, or at least an HDD with a SATA3 interface?

Answer 1

1) SATA 3 is probably only relevant for SSD.
2) The speed of the mirror depends on the processor and RAM (to a lesser extent).
PS
Do not forget to transfer the paging file to the mirror or disable it.
PSS
I did not bother and put Windu directly on the mirror.