CCP Blaze has posted a dev blog on the official EVE Online website detailing the various fixes and performance improvements made to the game client since the Tyrannis expansion. The piece goes into a fair amount of technical detail about everything from the game's physics, to Overview changes, to resource loading and memory issues.
"It turned out that there was an issue with the way the resource manager assigned a size to textures that had not been fully loaded. This caused the resource manager to hold on to too much memory; this was fixed shortly after it was discovered. We also found and fixed a memory leak in the module responsible for reading resources. At that time, during internal testing, we started noticing that some objects from our physics simulation weren't being cleaned up as well as they should have been. We fixed that as well," Blaze states.
Read all about it on the EVE Insider dev blog.