Good to know. But can you explain what a memory leak is? Or what could be causing it or how to fix it?
I'd like to know all I can.
On the PS3 there can't be a 'memory leak' in it's true sense, at least not like a leak on a PC. The consoles finite resources sees that this can't happen.
What is actually happening (although unproven and only a 'best guess' at the moment) is that the Cache the game uses, which is made up of 256mb GDDR ram, 256mb XDR ram, 512kb of L1 cache and 256kb of L2 cache on each SPE, is eventually becoming full as the game continually writes and overwrites the information stored in the combined cache.
In layman terms, the game fills and empties the cache continually as you move through the game, the problem is that a portion of data never gets deleted/overwritten and this remains resident in the memory, unfortunately as the process continues (as you play on) more data 'gets stuck' in the cache, eventually filling it completely thus preventing new data being written, which COULD be why the lag/stuttering is evident after prolonged periods of play.....for some people.
If this is the true issue, then the save file size, while it is a good indication of the data that's required to be streamed though the cache (i.e the larger the save file the more data being tracked by the game) it is actually not the cause of the problem.
Sorry for the boring tech-babble.