Looks 'pokey' enough providing that memory has been configured correctly. Presumably, the main bottleneck is getting large graphics files on and off the disk drive, in which case an SSD will help. Have you checked if the system is paging? If it is, more memory might be the answer.
Also, note that RAID 1 will slow down writes to disk drives, although reads will be unaffected.
Finally, if you have been given the task of optimising the performance of a particular graphics package, you will not be able to do this properly without running (and monitoring) the software concerned.
“Hollywood is like life, you face it with the sum total of your equipment.” -- Joan Crawford
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