Additionally, you should note that not all Intel HD 4000 are the same. In ultrabooks with low power ULV CPUs the Intel HD 4000 is clocked lower to reduce power consumption at the expense of performance. In Core i7 QM model CPUs, the Intel HD 4000 is running at full speed. As for the CPUs that fall in between, the Intel HD 4000's performance will fall somewhere in between.
If you want a laptop with integrated graphics for games, then you should look at laptops with AMD's Trinity APUs. The A10 series APUs will have the fastest integrated graphic cores.