Mybook thunderbolt duo upgrade to SSD

I have one 6TB my book thunderbolt duo which has 2 nos of 3 TB HDD - WDBUPB0060JSL-00
I didn’t use it that much. recently i started using that and its performance is too slow.
I am using for video editing (FCP) on my mac book pro through the thunderbolt 2 port.
I tried to do a speed test and got a result of 190-215 MB/s reading and writing speed.

is this is the real speed of this drive?

is it possible to upgrade the drive in to SSD?

if i upgrade my drive in to SSD can i expect much difference in speed and performance

Is there any external portable SSD available with thunderbolt 2 interface

all your advice is highly appreciated


Actual transfer rates will differ significantly based on system configuration. Performance testing by WD resulted in an average actual transfer rate for Thunderbolt of >250 MB/s on 6 TB systems and >225 MB/s on 4 TB systems.

Thank you Jonty for the feedback.
so what is this 10/20/40Gbps means?
how we can change the system configuration to increase the speed

what is the recommended external disk for seamless editing on MAC?

thank you for your advice