Unless you have 8 DIMM slots, it's a Mute point, assumming you specified the ram correctly.
You said 4 x 2 for 8 gigs.
That means 4 modules x Each module is 2 gigs, and it is very hard to stick 8 modules into 4 slots.
Like puting 8 pounds of sh$$ (that smelly stuff) into a 4 lb bag
ASRock Z77 Extreme4 LGA 1155 Intel Z77
Number of Memory Slots: 4×240pin
To go to 16 gigs you would have to go use 4 x 4gig.