Under normal conditions and setting memory accumulation should be nowhere near as bad. I use recount's default setting and in yesterday's 4 hour raid it clocked in at under 20MiB. But it really depends on your settings, if you set a lot of data accumulation you can make this worse. Make sure that you do not collect time data unless you absolutely need it. Also don't collect data for combatants that you never look at in recount (like non-trivial but non-boss npcs).
Even 20MiB is much for a pc like mine and I'm forced to not use recount any more even though I love it. I don't know if someone asked for it already since I ,obviously, didn't read all the pages on this thread, but is it possible to bring back the standby option recount used to have? It was very helpful to be able to disable recount without relogs if you didn't need it.
Thanks for the great addon. It's extremely helpful, and the best choice for me. :)