hypers is short for elpida hypers and they are the memory IC on the ram (google if you are not sure), i'm not too knowledgeable in computer hardware but what I do know is that they are generally high-end ICs that allow for much tighter timings or higher frequency compared to other IC brands.
For example, an elpida hyper IC could probably run that ram at 6-6-6-18-1T @ 1600MHz or probably even tighter but note that any Corsair ram which have tRCD timings (basically the 2nd number in the timings, 8-9-8-24) that are 1 above the rest generally do not contain elpida hyper ICs.
I checked with Corsair forums after I bought my ram and they helped me confirm that the particular model of ram that you are buying has ICs made by PSC, hence the reason why it is cheaper than other high-end ram from Corsair that are hypers (got my 4gb for around $185 CAD before tax, top end hypers from Corsair are usually around $150+ per 2gb stick).
If you are unsure whether or not you got hypers or ram made by PSC, you can go here: http://forum.corsair.com/forums/showthread.php?t=68811 and check the version number found on the back of the ram to see which IC it has.
Whew, hoped this cleared things up