I am playing on a 3440x1440p display with a 1080 ti. I have overclocked my 6600k to 4.4 GHz with 1.360 voltage and it's still bottlenecking my system. Would it be worth upgrading to the 8600k?
You will need, at the very least, a Z370 motherboard if you decide to go for the 8th Gen Core i-K suffix processor. What sort of tasks do you laden the system with? Those volts seem high as well. Lower 1.3v would be ideal overclocking.
Unless you want to upgrade motherboards too, your upgrade path leads to a 7700k, but you'll want to beef up the cooling and de-lid if you want that horse to run. No need to hold yourself back with an i5 when everything else you're doing is premium.
I would wait for 9000 benchmarks. If You are going to buy a new motherboard then I would go z390. And a new CPU.
The 6600k will bottleneck a 1080ti some, but I dont think you are going to get much improvement from even a top level CPU at 1440p as higher resolutiins have less strain on the CPU. The cost wont be near the reward IMO
The i5 6600K is a good CPU. I don't understand why you think it's bottlenecking especially at such a high resolution. If you must upgrade the 7700K is your best option.
The i5 6600K is a good CPU. I don't understand why you think it's bottlenecking especially at such a high resolution. If you must upgrade the 7700K is your best option.
There are some newer AAA games that really need more than 4 threads to run well nowadays, eg. the two most recent Assassin's Creed titles, Watch Dogs 2, Battlefield 1. Having run a 6600k and 1080Ti combo myself at one point, I could see the CPU being a bottleneck even at 1440p ultrawide.
Unfortunately Intel's decision to not allow Coffee Lake to work on older LGA1151 boards does make an upgrade an expensive proposition. The 6700k or 7700k are the only real upgrade options that don't require a motherboard change, and all that gets you is hyperthreading, which is enough to keep up with most games for now, but might only be good for another couple of years until games start needing 6 physical cores to not choke.