The Zalmans are not great heatsinks.....the 9700 is the same poor design as the 9500, just slightly larger. A minor face lift that doesn't help temps very much.
As I said in your other thread, be sure to take Vcore off AUTO, otherwise it will continually increase Vcore as you overclock when it is not needed.
For 24/7 operation, I would try to keep the CPU at 50c or so, defiantly not to exceed 55c which is the recommended maximum for an overclocked Core 2 Duo. Looking into a better heatsink would be highly recommended. The best heatsinks are block style with a changeable 120mm fan.....you want a lot of surface area and you want ALL of the surface area to have air forced over it in a single direction. the Zalmans just "swirl" the air around the fins, with the direct airflow of the open fan going over only the smallest surface area.