3DVelocity posted a review on the OCZ EL PC3500 Gold GX XTC

One of the main arguments against the use of heat spreaders was that any benefits they gained from distributing heat evenly throughout their entire surface were lost by trapping hot air beneath their surface. When you take into account the need for some kind of thermal interface between the memory chips and the heat spreaders, often nothing more than a semi-efficient thermal tape, it was reasonably argued that having the chips open to direct cooling from the air circulating in your case is likely to do more good than cloaking them in a metal shroud, however efficient it might me at conducting heat.

OCZ EL PC3500 Gold GX XTC Review