4890 lcs termal paste

just a thought here for the past couple months the temps on my 2 power color 4890 lcs (came with ek waterblock already installed) has been minimum 34 degreed celcius. whereas my 940BE idles at like 24-28 degrees celcius. it just occured to me that the 940 has zalman brush on thermal paste and the power color cards have whatever thermal paste they came with. how many degrees do you think changeing the stock thermal paste with the zalman stuff would be good for.

also does anybody know if i would notice a differance if i switch formt eh zalman stuff the the artic cooling stuff. thing about the zalman stuff is with the brush on applicator its so damned easy to to apply.