It does show a small gain, the big issue right now is that AMD doesn't support triple channel. If they did the gain would be more.
But either way your 940/AM2+ mobo/DDR2 ram is end of the line. You can keep tossing AM3 procs in it for sure, but when AM4 rolls out or AM3+ and people can rotate their CPU's up the AM2+ chips will not have that.
Like I said just future proof, plus if your a gamer most games only use 2 cores. So this setup saves you some cash and gets you a system that is just as good for gaming, and is more future proof. win/win/win
tri chan really isnt the issue, the k8/k10 chips are not that diffrent and dont bennifit from crazy bandwith as much as intel chips do, go back and look at ddr1 vs ddr2 and ddr2 vs ddr3, the gains are small, the chips just arent designed to need the massive bandwith intel chips have relyed on.
sure more bandwidth could boost a few apps, but it wont have the massive effect your implying, you could use the best ddr3 on the market with low cas and crazy clocks and its not gonna give much of a boost over a decent ddr2 kit.
as to the overclocking, each board+cpu combo overclock diffrently, you really cant say that all am3 setups are going to clock better then the same am3 cpu in various am2+ boards.
few examples, i have had ALOT of socketA and 754 chips and boards, some chips just work better with some boards/chipsets/bios, one chip i had HATED every board but my chaintech vnf3-250, wouldnt get past 2.5, on the vnf3 it went to 2.8 with almost no effort(was a clawhammer cg 3700)
socketA chips, some boards+center stepings/scews clocked better then others, i had great luck with the l7s7a2 and certan 1700+ scews, could get them to beyond 3000+ specs with ease, but the same chips didnt clock quite as well in my far more expencive abit nf7-s or epox boards(yet other stepings clocked great in them)
I see the point if ur building all new and can get a good deal on a good/great am3 board, but currently the list of pure am3 boards is a bit short for me and they are all pretty new, so issues arent uncommon.
and how is the 940 the end of the line when you can stick any am3 cpu in an am2+ board and overclock it? its the last purely am2+ cpu, but that really dosnt matter(i would probbly get a 720 over 940 anyway till they get some lower watt quads out)
no board has out lasted the one i have in here now the biostar ta770(non-se) can take any am2+ cpu you wana toss in her and overclock it with ease, by the time i replace this board most likely 3rd gen am3 boards will be out, and by then maby there will be a real reasion to move to am3/am4 (or whatever its called by then)