H100i thermal paste, stock or arctic silver 5?

The question is pretty start forward. Should I leave the H100i stock thermal paste or would I see improvement by putting the arctic sliver in there. I have the arctic silve from an earlier build I just completed but am not sure if the stock paste is better than arctic silver or is it the other way around. What are your opinions? 

CHANGE THE PASTE!!! XD

I have used the stock corsair stuff when I had an H80 and it was 'fine' but if you have some other good aftermarket, fly at it!

If you have some AS5 I'd go with that. AS5 will perform a lot better over the life of your cooler/CPU. The nice thing about AS is that it doesn't dry out over time like the pre applied TIM, or even the lesser quality TIMs. I've been using AS since shortly after they hit the market. I'm biased though since they got started and are still located about 40 minutes south of me.

Corsair uses some pretty decent stock TIM. You won't see much improvement. Barring some of the more exotic TIMs, for most of the quality, brand-name thermal compound you will only see about a 2C difference, which is within the margin of error.

Arctic Silver 5 is an oldie, but goodie. It has been eclipsed, especially in terms of cure-time, but there is nothing wrong with it at all.

Want a high performance Thermal Paste? Try the Gelid Solution GC Extreme. It's a little more expensive but ell worth it.
http://www.tomshardware.com/reviews/thermal-paste-performance-benchmark,3616-11.html