Well, with 8GB of ram, it would serve very little purpose.
But either way, the PC is going to chug a while on boot even without RB - superfetch has 8GB of ram to fill up. And the chugging isnt damaging performance as much as it sounds like it is - not all chugging is made equal. Theres the bad, swapping chugging, and the something is loading chugging - both which lead to slowdown. The SF chugging is a loading in the background, sounds like its slowing you down but isnt really kind of chugging. So try and ignore it - its normal, and its a good thing.
The solution? Dont shut down - use suspend instead, which takes next to zero power (2W or so), and it pops right back on in a few seconds rather than the few minutes booting takes.
One thing I've noticed - the RB cache seems to be initially filled with the exact same data SF caches. If you plug in a stick long after you're already booted, it wont hit the HD at all but it'll fill right up. On high memory systems, the only purpose RB seems to serve is a quiet, quick way to refill the SF cache after you close a huge program.