Right, here we go so you can quit moaning about memory...
A simple quick mission with the ROTOL Hurricane at Tangmere, CEM off so I can get it rolling fast, view was swapped out to F8 and left at default level of zoom which enables a nice big cloud of dust to be kicked up and prove my point.
Left hand set of arrows, GFX options set to 1680x1050, everything maxed apart from SSAO and Epilepsy Fliter, you can clearly see that memory useage is held just under my cards available memory, the big dip in fps is when the dust kicks up properly and you can also see there is no significant change in memory useage even though there is still memory available.
Right hand set of arrows is the same senario, only I've dropped to lowest resolution available and turned everything to minimum apart from effects, again, no significant increase in memory useage even though I still have some 500mb+ free but a significant 50% drop in fps when the dust kicks up.
It is clearly a render issue and not memory related.
And even more compelling, fps up above 400 with vsync turned off with everything except effects set to lowest, you can clearly see the major impact the take off dust has to performance with no regard to memory useage.
Obviously it could always be an issue with my drivers or driver setup but I cannot get onboard with it being a memory issue whatsoever.