I was more properly referring to CPU scores which are the only ones benefitted from HMP.
I ran a quick AnTuTu (cpu) test to my Exynos 5420 equipped note and here are the results:
http://i.imgur.com/zD32DZQ.png
Notice how remarkably similar they are to note neo's cpu score:
http://www.gsmarena.com/showpic.php3?sImg=newsimg/14/01/sgn3n-leak/gsmarena_006.jpg&idNews=7538
Note that note neo has only two large cores which are clocked lower by 10% compared to exynos 5420 and it still posts almost the same score merely by employing the help of the small cores. Now add two large cores more and you'd get 50% more performance, it's simple math really...
Now I'm not saying that it would be a performance that we would actually see in most occasions , it would either be throttled or -even- not supported by most apps but still it's potentially there (which was my point by saying "up to").
What will *definitely* be there if HMP is to be enabled is better battery -though- as it would make more efficient use of the small cores. Since exynos 5422 is also on 28nm yet has HMP enabled leads me to believe that we lack HMP for strategic reasons (so that samsung will sell more exynos 5422 / qualcomm equipped machines)