I use Chrome on a slower PC. Although Chrome consumes more RAM than Firefox does, it actually feels noticeably faster on any PC. On old slow PCs (and mobiles) this makes a hell of difference. Firefox became usable again when it abandoned XUL (for some years before that it was pure torment to use so I had no choice but to switch to Chrome) but still isn't as fast as Chrome is. I only use Firefox happily on faster PCs.