Er... you SHOULD have a CPU bottleneck in a lot of games... ESPECIALLY twilight princess. I don't know if it's still the case, but a hack for that game was removed a while ago, and not even the best CPU for dolphin can run it 100% all of the time. (note: possible slight exaggeration)
Also, a 7850 really shouldn't have problems with dolphin. If you're adamant that something with your GPU is causing dolphin to run slowly, I'd say to try overclocking it. I believe the HD 7000 series were the first AMD cards to support memory voltage control (correct me if I'm wrong on that), and memory is what you'd need to overclock for dolphin. If the problem persists, or you have other reasons for buying a 290 (ex.: benchmarking, competitive overclocking, really slow bitcoin mining, etc.), then you should get it. But, keep in mind that companies aren't allowed to release 290s or 290xs with custom coolers yet (I think the date was march that non-ref 290s and 290xs would be releasable), so you'd either have to slap on another cooler or deal with the horrendous reference cooler.
Also, a 7850 really shouldn't have problems with dolphin. If you're adamant that something with your GPU is causing dolphin to run slowly, I'd say to try overclocking it. I believe the HD 7000 series were the first AMD cards to support memory voltage control (correct me if I'm wrong on that), and memory is what you'd need to overclock for dolphin. If the problem persists, or you have other reasons for buying a 290 (ex.: benchmarking, competitive overclocking, really slow bitcoin mining, etc.), then you should get it. But, keep in mind that companies aren't allowed to release 290s or 290xs with custom coolers yet (I think the date was march that non-ref 290s and 290xs would be releasable), so you'd either have to slap on another cooler or deal with the horrendous reference cooler.
in a perfect world we would all be piles of sand with no ability to form coherent bodies of body