Well, I've been running my trusty AMD X2 6000+ for years now. When the Phenom 940 and 720 came out, i thought i would give them a shot and see if I got some incredible performance.
Well, my 3DMark06 scores went up, but any noticeable performance increase in real life? Actually no. As a matter of fact, it seems my 6000+ running at 3.25 makes my desktop software run FASTER AND SMOOTHER than the 940 or the 720! Yep, i was surprised too. Gaming? No difference. My 4890 handles everything i can throw at it except Crysis and even at that I get playable framerates. As far as I can tell, CPU's made no difference at all.
So, if you have the 6000+ should you buy the new Phenom II's? In my opinion, no. unless you are doing computing which relies upon and uses more than 2 cores, save your money.
PII 940 should have given you all around improved performance, although it would not have been a tremendous gain in single threaded. There definitely should not have been anything that lost performance.
Did you just drop the new CPUs in without reinstalling Windows? From personal experience, that doesnt work so well.
I got the ASRock AOD790GX-128M motherboard and an X2 4400 to just throw together as a decent little HTPC. I had installed Vista when I found a good deal on a 940 and 4870 1GB, so I jumped. I updated my BIOS, and proceded to drop in the PII. My performance and stability went right in the crapper untill I preformed a reinstall.
lol. did you consider the resloutions you are playing it at? at low and mid resolutions even a pentium dual core e5200 with a 4890 would look good....moreover saying that a x2 6000 clocked at 3.2 would outperform three cores running at 2.8 with 6 mb cache coupled with a 4890 is hard to believe....don't get me wrong the 6000 is a solid chip after all not too long ago it was a flagship processor however it should not under normal circumstances be able to outperform a phenom 2 at stock speeds and cannot compete with them for overclocking that's just a fact.
i got a free x2 5600 be (or was it a 5800be?) which i oc'd to 3.2 (default 2.8). it was great for 6 months until i got the x4 940. i oc'd the x4 940 to 3.5 on same mobo, ram, v8800gt and saw huge jumps in some games (cod5, crysis, dirt & grid, company of heroes). not to mention i can now play cs source with over 20 bots and have no performance degradation (used to max out at about 12). plus my vista 64 overall experience is better. don't get me wrong, the x2 @ 3.2 was fine, but my x4 @ 3.5 destroys it (even the 3.0 stock was better).
im running my 6000+ into the ground (I get 35 fps avarage fps on crysis, with max settings)... but that said, a Phenom II tri-core 720 should wipe the floor with the 6000+. There must be something wrong with your set up.
Desktop wise, the more threads the better.
Im also interested as to why you have both a 940 and a 720.