What's tricky is that for most people it never really does cure properly as they don't turn the system off and let the cpu and heatsink cool down to room temp 3 or 4 times a day like you really need to do during that 200 hours. Plus it needs to be cleaned off and re-applied once a year requiring one to go through that entire curing process (200 hours is 8-9 days) all over again. If you get a bad seat and have to re-install you need to go through that entire curing procedure again. Even after going through all of that the chances are that temps will be 2 to 5 C HIGHER than the other top brands.
AS-5 is so outdated and under-performing that NO ONE should be foolish enough to still use it. IT hasn't been a really viable or worthwhile TIM since 2004 or 2005. MX-2, MX-3, MX-5, IC Diamond, CM Thermal Fusion 400, Shin Itsu, Noctua NT-H1, and the other top TIMs have a curing time of 1 hour or less, some as little as 5 minutes. With all of that in mind along with the fact that AS-5 is more expensive per Gram than the others makes it a very poor choice of TIM. I feel sorry for any un-informed individual who drank the Arctic Silver Kool-Aid and continues to use it when there are so many other better quality and less expensive TIM's available.