It is precisely the fact that K-Meleon is so light on resources that it has become my favourite browser. It's even lighter still if you block flash by default (Flash is the greatest culprit for burning browser resources there is, it's a menace).
I run several websites and have multiple online interests. This means I like to have LOTS of tabs open. Not to mention, I have an old low spec PC. YET, I currently have one KM browser window open with 31 tabs open, a second KM window open with 38 tabs open, a third KM window with 28 tabs open and two other KM windows open each running one tab. That's a total of 5 KM windows and 99 tabs. And many of these windows and tabs have been open for over two days. Yet, with all that,KM is using only 222,944 K of RAM (although, it's usually much less) and between 4 and 41% (up and down between those numbers) of CPU. Moreover, KM remains stable and has lost NONE of its speed. And as I said, this is a low spec machine. No other browser can do that, certainly not on my box! For performance and sheer capacity, I LOVE this browser
And it's got good security too (not to mention, Spywareblaster has support for KM). It's not just great for lower spec machines, it's also good for higher end machines where you want to run lots of other resource intensive software at the same time.
And one final thing, I like the lack of running process clutter too. It has just one, whereas IE for example, has a process for every tab you have open. Yet, even with only a single process for tens of tabs and multiple windows, KM will still recover all those tabe for you in the event of a rare crash. And whilst on the subject, during my six months regularly using KM, never once have I needed to kill it via the Task Manager as I've often had to with other browsers.
If you want to lower resources even further, block Flash! Even if you want to watch flash videos or play flash games you still can. You simply don't have all that other flash you DON'T want to be running, as you're not using it. Flash will use up browser resources even if you're not playing the video and it's not in the tab you have open. It's the # 1 cause of browsers maxing out and if you block it, you'll really notice the difference in the resources your browser is using, no matter which browser it is. A Hosts file is also a good idea,as all those adverts can use a lot of resources, not to mention be a security risk (also block third party cookies and turn off Iframes). I've never tried pushing KM to its limits, but it would probably be able to run 200 tabs or more, for extended sessions, on my rubbish machine. I couldn't even contemplate that with any other browser.