Yep, to get 7.9 all across spells out a $3,000+ rig. My Daughter's gaming rig is 7.9 across, but it was $4K+ and runs everything OC, 3-WAY SLI, etc.
The following is my wife's rig, pseudo i7 workstation. The i7 930 cannot be OC to 7.9 requires a 6-core; even OC > 4GHz yields ~7.7 or less; an OC 980X will give you 7.9. RAM - my wife's has 1600 C9 Dominator but my Corsair Dominator TR3X6G1600C8D does hit 7.9. I have CF HD 5770 7.9/7.7 ; wife's 7.4/7.4. Oddly, build them but don't really game much - go figure.
Wife's rig ($1,600 in May/~$1,400 Dec):