1050ti with i7 7700k?

Solution
I7-7700K is about as good as it gets for gaming.
The processor is strong enough for good gaming even with a GTX1080ti.

If, however you are planning on buying both, reconsider.
It is usually better to budget for a stronger graphics card.
The budget for a i7-7700K and a GTX1050ti is something on the order of $470.
Using 7th gen, a i5-7600K and a GTX1060 would be better balance.
The i7-7770k will be more than enough for what you ask, but the 1050Ti is the limiting factor. Even at 1080p, you'd want a 1060 6GB, or an RX 570 or 580.

If you're running higher resolutions, then you'll need to at least go 1070/Vega 56, depending on the resolution.
 
I7-7700K is about as good as it gets for gaming.
The processor is strong enough for good gaming even with a GTX1080ti.

If, however you are planning on buying both, reconsider.
It is usually better to budget for a stronger graphics card.
The budget for a i7-7700K and a GTX1050ti is something on the order of $470.
Using 7th gen, a i5-7600K and a GTX1060 would be better balance.
 
Solution
The 7700k is a great CPU. But in my opinion a 1050ti is not a good paring. It is like having a Ferrari but with cheap tires and cloth seats.

For gaming the GPU is much more impactful for performance than the CPU. I would not recommend building a gaming system where the CPU cost more than the GPU. I really would not even pair a 1060 with the 7700k. You would get a much better price vs performance ratio with the 7600k.

 
The i7770k is not a 144hz gaming cpu, as some say. The gpu is the most important part for 144hz. Personally, i don't know why you would want to pair a 1050Ti with a 7770k, unless you are on a budget. If on a budget, a non-k i7 or i5 K series with a good air cooler, and a 1060 6GB would be a better option for 1080p gaming. If you want 1080p 144hz gaming on high settings with no drops in fps then you have to step up to at least a GTX1070.
 


For 1080p gaming, the gpu will become the bottleneck way before the cpu. My R7 1700x @3.925mhz on my 1080Ti can eaily push 144fps@1080p. But its my opinion over yours. Personally I'm running 1440p/4k @ 60fps. Keeps my card cooler. I prefer visual detail FPS.

Price wise the 8700k in the UK is about £80 more, plus more for an appropriate mobo. So about £100 - £120 more for cpu and mobo combo. For £120, you can go from a 1060 to a 1070, or even a 1070 to a 1080. Upgrading gpu will make more of a difference.

I agree - GTX1070 minimum for 1080p high/ultra settings.
 


Actually, when gaming at 1080p, the bottleneck is on the CPU, not the GPU. This is why at 2k and 4k there are little differences between the CPUs as the GPU has to work much harder for the extra pixels. This is why CPU benchmarks are run at 1080p, because at higher resolutions the differences between CPUs are nil.

But either way, he is not going to get 144hz at 1080p with a 1050ti unless he is running on low settings. The bottleneck here will be the GPU. The only reason to go with the 7700k now is if he plans on getting a new GPU soon. If not, he should get a cheaper CPU and use the money saved to get a better GPU.
 


Depending on prices where you live the i5 8600K should cost less and give better performance 6 real cores, freeing up enough money to get a GTX 1060 with it.
40 bucks less better performance going by US prices.
https://pcpartpicker.com/products/compare/VKx9TW,Mr2rxr/