Please Help my members are not shown as being online the light bulb is

I'm having a problem since i upgrade to 7.4  whenever a member logs in it is not being recorded the member has access to the site and all feature but they are not shown as being logged in... this problem is also affecting my simple messenger since members are not recorded as being log in they have no access to the messenger system I really need some brilliant minds to help me with this issues its been going on for 2weeks and i cant resolve it

I'm using 7.0.4 and have the same issue, by turning off all file cache options the site stats

updated properly/quickly. I haven't narrowed it down to exactly which one controls this yet though.

Any hints from the all knowing??