If your looking at both of these, then it's a tough call. The Lenovo has a quad core i7 vs the dual core i7 in the hp. But the HP has a 740M vs the Lenovo Integrated 4600. I'd say, spend the extra cash and pick up one of these:
Lenovo z510 is one of the latest laptop by lenovo. This one consists of the latest Haswell bridge introduced by Intel, and has a good clock speed. The ram functioning and speed is good, as compared to hp, hp is trash, they don't last long and have heating problems. This laptop is ideal for gaming and multitasking, and has both integrated Intel HD 4000 series and dedicated Nvidia gt 740m, depending on the model you buy.