I have the lenovo y510p also and i have notice that many people are getting NGFF MyDigitalSSD which i would recommend because it has great performance and that you should install an OS onto it also, and for the 2.5 sata drive you should try to get an ssd like for an example a Samsung 840 pro which is a good ssd and if you are going for a hhd then you should consider a 7500 rpm or higher rpm drive like a wester digital caviar black 7500 rpm and if u get either one of them that you should consider installing an OS onto the NGFF MyDigitalSSD and use the 2.5 drive as storage.