Sure, Apple Mail uses about half a GB, too (same mailbox as I just loaded in Gmail, even). But that's the
whole program, with several HTML emails open (a large thread) and my entire inbox scrollable instantly at once. Major view-switches take maybe 300-500ms, and its idle CPU use sits at 0.0%, not a constant 0.4-2.5%. And it doesn't have to reach out to a server to search, so some of that (I'm guessing quite a bit of it, actually) is likely in-memory search cache. That with what amounts to
two of gmail's pages open (an email thread view, and a mailbox view, side-by-side—I only had the latter open in Gmail to achieve this much memory use)
Unlike Gmail and other google properties, I can leave it open for weeks and forget it's there. It doesn't affect overall system performance—because it's not demanding CPU time and forcing context switches when it's not doing anything.
[EDIT] incidentally, has Thunderbird bloated a ton or something? I used to use it on machines with 256MB of memory total and it was not the only thing I had open, and it was totally fine. And yes, HTML email existed then. I was under the impression it was—thanks to neglect, basically—still on good, old tech and the plan to "improve" it to ditch that for bloated modern junk was still on the drawing board.
