Hi,

I think you can still stay on your RAID5

The following link http://www.dell.com/downloads/global/solutions/tradeoffs_RAID5_RAID10.pdf?c=

can explain you more. However if you can place your log and tempdb on a RAID 10then it will be a good plus.

But it depends, if your reads increase then a RAID10 may be better option, if not then you'll not obtain a significant gain, moreover considering your log and tempdb already on a RAID10.

Regards

IgorMi