RealBeast :
Gaming is not helped much by using an SSD. An SSD is very helpful for video work, and the more important specs are the 4K R/W and IOPS.
If you are using Adobe products for editing a small scratch secondary SSD is also very helpful.
thank you for answer ,it will help me so much .
one more question, if you want to pick a SSD below 100$ what will it be ? I've found
Corsair Neutron XT 240GB & Samsung 850 Pro 256GB , for my purposes which one would be your choice ? samsung 850 is about 110$.