Question on ram cooling

[ikpthegame]

Ok so I was having some heat issues with my 290 and put on a aftermarket cooler. One of the ram sinks will not stay stuck on, how important is it to have a sink on the ram of these cards?

 

[ATMINSIDE]

If the stock heatsink touches the RAM, you should have one on it.

 

[saturn]

If the stock heatsink touches the RAM, you should have one on it.

This.
What cooler are you using?

 

[ikpthegame]

Not the stock one, I forgot what it's called, I'm not at home.