Aurora R7, upgrade needed for games?

Hello,

Have been experience some issues when playing games like Rust on my Alienware.

See specs below:

• 460W APFC PSU Air Cooled Chassis
• 1TB 7200 RPM SATA 6Gb/s (64MB Cache)
• 8GB, DDR4 2666MHz
• NVIDIA(R) GeForce(R) GTX 1070 with 8GB GDDR5
• Intel Core i5 8400 (6-Core, 9MB Cache, up to 4GHz with Intel Turbo Boost Technology)

Game is super slow to load, choppy and sometimes freezes.  Occasionally gives me a message to upgrade the RAM. 

Should I get another 8GB or jump right to a single 16GB?
Do I need to upgrade the i5?

Thanks,

kyle