Make sure it's a 2015 with a 970m. Not a 2014 with a 870m as Wullfz linked. The 970m is Maxwell-based and is relatively cool for the performance it delivers (it's still a 75 Watt GPU). The 870m is a Kepler-based bastardization which Nvidia was forced to bring to market to tide them over because the fabs failed to move from 28nm to 16nm. It's 100 Watts and performs about on par with the 960m. The 970m is about 30%-50% faster than the 870m.
The fabs failing to move to 16nm on schedule is basically why there was no desktop 8xx lineup. Nvidia had designed Maxwell assuming 16nm, and when they were forced to implement it on 28nm the larger designs (desktop and high-end laptop) turned out to have problems. So they scrapped the 8xx desktop GPUs, and re-used the Kepler architecture for the high-end laptop GPUs.
If I remember right, the screen on the 2014 sucked as well, while the 2015 screen was one of the best on any laptop.