yes there will be bottlenecks but it won't be too bad if you could overclock that cpu to around 3.4ghz. That should give you acceptable gaming performance.
If you decide to get a z68/77 motherboard with any sandy/ivy bridge quadcore i5 processor, that would keep you set for the next 2-3 years for sure. You can upgrade to any gpu under the sky with that setup.
My resolution is 1680 x 1050 and I do not want to upgrade that I'm fine with it. also the 7970 uses a lot more power and since I only have a OCZmodx 500 watt PSU I don't think it could handle the extra power draw since I think my CPU does 180 watts or something already...
no phenom 2 x4 uses more than 140w at stock and some only 125w. this
would go up if you oc though. also the linked alternative was 7870 not
7970 and both cards seem to have two 6pin due to the inclusion of 2
2 molex to 1 6pin power adapters with both mis cards. card length may
be an issue for you though, since the egg says the 7850 in question is
under 8in long and the suggested 7870 is over 10.5in long. good luck.