Use ～たところで when you want to concede a hypothetical action but dismiss it as pointless — "even if X were done, it wouldn't help." It is stronger and more resigned than plain ～ても, and the second clause is almost always negative or expresses futility (変わらない・間に合わない・意味がない・とは限らない). Common in reports, negotiation, and written argument where you preempt a course of action as ineffective; frequently reinforced by いくら・どんなに・今から.