Ivybridge is also in par with Haswell and Skylake in gaming... As well as SandyBridge but thats starting to fall already, But is still good for todays AAA titles.
Yes. And my Core2Duo with DDR2 4-channel and a modern mid-range GPU also could probably go above low while preserving 30 fps. After replacing the e8600 with a Xeon 771—>775, I would probably be getting playable medium/50 on reasonably new titles (largely due to 4 physical cores, which is something i3's don't have and Pentium G's don't even pretend).
For me it made little sense buying old tech, but it really makes little sense to change platforms for any gamer with anything 2nd gen and up, except for those CPU+mobo deals that cost basically the price of the CPU alone, but they don't normally involve top boards. The upgrade path in those cases IMHO leads to the strongest CPU the mobo can (be made to) support (including Xeons), followed by GPU. And sometimes GPU first. Some fancy RAM maybe, just maybe. Or faster SSD. But hardly platform upgrade.
I considered a new FX (8370e), figuring the lower power requirements might put it where my mobo can handle a decent OC, but my 6350 is running at 4400 MHz now and doesn't use all 6 cores anyway. I'm looking at just biting the bullet and getting a 6700 Skylake and SSD. A GTX 1070 on that should put me in good shape for an all around PC that games at a decent level. The RX 480 is tempting, but I've had nothing but problem's out of AMD's drivers for so long I don't know if I can buy another Red card. LOL
You may be experiencing some perceived slowness in the system due to the lack of an SSD, so I would consider starting from there (+ full system reinstall if it's been a while). If you were absolutely sure you wanted a Skylake board, then it could make sense to get an NVM M.2. on 4 PCIE lanes because good deals can be found on used ones with reach people replacing 256 GB drives on day one. But otherwise (and you'll probably need a storage drive anyway), I would get the best deal on a (used) Samsung 850 Evo, which is the fastest SATA SSD bar Samsung's own 850 pro, which costs double and is
not 100% faster, or whatever 480+ drive with similar rated transfer times and new production date happens to cost much less, if at all. (Preference for Evo by default anyway).
I've just checked with User Benchmark, for what that's worth, and
the 8370e seems to have a 0% difference from the 6350, just overclocking a tiny bit better, so I wouldn't try that. In fact, it seems the 9590
might not be terribly faster. So yeah, it makes little sense topping out the slot unless you could somehow make a good deal selling your current CPU and buying whatever's fastest that fits in. I should've checked this earlier, but I'm not really familiar with AMD, so I didn't realize how close your CPU already was to the best the slot could hold.
For a platform change Skylake would be the default choice for most people (though some deals on older top-of-line CPUs and mobos provide more performance for the money), but it could be worth considering other options if you want to keep the memory, and you have some good memory there. Still, the mem shouldn't be hard to sell, and the last time I checked a single stick of HyperX Savage DDR4 16 GB could be had for $60, so selling DDR3 and buying DDR4 could be a good deal actually.
All in all, if I were you, I'd probably attempt to swap the mobo and CPU only, as long as I didn't have OEM Windows, and I would probably be looking on Ivies and Sandies. Otherwise, probably Skylake. However, once you've got a box version of Windows that you don't have to bury with your old mobo, the problem is over, and you're 'eligible' for quick platform upgrades from that point onward (meaning only CPU+mobo, not even RAM).
(Using 1.5V DDR3 with a Skylake mobo is a poor idea, even if it will let you. People say it's led to damage.)
If you're on OEM Windows, it might be the best idea to sell the computer and build a new one, especially if you could do something to increase the (perceived) value at a low cost to you (e.g. take the trouble of buying a cheap used SSD and reinstalling the system on it for the next owner), but obviously not if it's going to bring you like $200 for the whole rig.