'premium branded' means nothing to me, just means a company has a big head.
4GB is the 'standard' amount of RAM these days, and DDR3 is the fastest current RAM Data rate (Dual Data Rate Version 3 (DDR3)).
8GB is alot of RAM for most cases, and 'premium branded' doesnt say anything about speed or frequency.
RAM (Random Access Memory) is a volitile (e.g. it gets emptied when you turn the PC off) temporary storage for open programs. Any program, service or application you have running will have temporary information stored in the RAM, when you close the program it is removed from the RAM.
EVGA SLI Micro Z68 // Intel i5-2500k // 8GB Corsair Vengeance 1866MHz // Overclocked 2GB MSI R9 270X // Corsair Carbide SPEC-03 // Kingston Hyper-X 120GB // 2TB WD Green + 500GB WD Black