The T-Mobile G2x is already a great smartphone from LG with good performance. It already has a NVIDIA dual-core 1GHz Tegra 2 mobile processor and graphics chip returning benchmark results of around 2,500 in Quadrant.
If that performance is not enough for you, now by using a custom kernel, T-Mobile G2X processors can be overclocked to 1.5GHz. Though there are similar kernels for G2X users on Gingerbread, this particular kernel is for Froyo only. The overclocking of Tegra 2 makes it super fast with new benchmark records. The 1.5GHz clockspeed is a 50% increase in clock speed which returns scores of 3,264 in Quadrant.
This kernel is kind of new and still in its beta stages, though no issues have been experienced using the kernel so far, its still not fully tested and stabilized. So even though no problems have been faced, it is not recommended to play with your brand new Froyo phone. Well updates are on the way to make it more stable.
As a word of warning, stressing the CPU for more speed will also consume more power and hence draining your batteries much sooner. Anyways, if you are someone who wants to experiment please continue overclocking your phone to over 50 percent and play with the new custom kernel by following the instructions here.