I encountered a similar issue awhile back with a Chrome-based terminal emulator, which this would also solve. Every time it outputs a line, it scrolls to the bottom, which forces a reflow; and if the scrollback is long, the reflows get slow, and performance ended up being really pathetic. The solution ended up being a hack to prevent the per-line reflows (Javascript scrolling and bottom-relative positioning), but this would be a better fix.