preassembled

Hi everyone. I'm going to upgrade a preassembled core i5 (6th gen.) Trust desktop, which is going to be used for everyday usage and for very light gaming. So, the rig is: Core i5 6th gen(as mentioned before); Trust 1151 mobo; 8gb ddr4 ram; 128gb kingston ssd; 500gb hdd (for storage); 250w psu...