I suggest throwing the spec sheet out the window as well as most synthetic benchmarks. Unless you know more in depth info of what you are looking at, comparing specs is more misinfo than anything else since specs can't be compared with different architectures. 128bit being better than 64bit is correlation not causation. You can also see a 730 64bit gddr5 beat a 240 128bit gddr5 by quite a bit. R&D will put a wide enough bus for what the gpu needs and different memory algorithms will affect bandwidth usage. For giggles, a 9800gt 256bit loses to the 730 64bit. Clocks can't be compared when cores do different amounts of work at the same speed (same for cpus). 384 kepler cores actually loses to 192 fermi cores (which is also older) so can't go by core count or if one gpu is newer. I think you get the point. Ms removing wei in 8.1 and later was one of the best things they did. I never saw any professional review give wei scores.
http://www.tomshardware.com/reviews/gpu-hierarchy,4388.html Tom's has this easy to see hierarchy chart based on average performance in a number of tested games. Very convenient. It is missing some rebranded cards like a 610 but it's on there as a 520. Techpowerup has nice graphs and compares different res too but you don't see low end card reviews too often on there.
That 350 is single slot but a dual slot cooler which will not work. Many single slot gpus stopped being produced so a 730 is the best I could find right now.