Help - high temps for intel i5 2500k w/ antec h20 620

i am a new oc'er and just built my 1st gaming pc.
i have a intel i5 2500k setup with watercooling Antec kuhler h20 620; and i have the 620 running dual fans in/out

from youtube videos of pcwizkid his i5 setup with air cooling;
and also with funkykit's review of antec 620 : thier temps range from 25'C to 32'C at idle, at stock 3.3ghz
http://www.funkykit.com/component/ [...] ml?start=5

i plan on overclocking it to 4.5ghz but i dont want to yet because my temps seem too high....

i used artic silver 5 thermal paste with above listed setup and my idle temps are between 38- 41'C in idle
and 70'C when 100 load with prime95. my case is the Rosewill Future gaming case, which i have 4 120mmfans intakes with plenty of vents / mesh for outake

would i need to reapply new thermal paste, or use diffrent one, what could be causing this.. please help any advice?? does AS5 cure time affect this...