LOL! And you're wondering why it's 50MB?
30,000 lines per channel * 15 channels = 450,000 lines it has to keep in memory.
If you figure 50 characters per line average, that's 22.5MB right there without any scripts loaded. And you may have more that 50 characters per line average.
Unless you really need such a large buffer, you should drop it to 5k or less. Your memory usage will drop significantly.
