Motherboard and CPU Recommendation for Heavy Excel User / Occasional Gamer

[CodenameAter]

First time poster looking for a recommendation to upgrade my current system. Here are the criticals on my current machine:

Operating System: Windows 10 Home 64-bit (10.0, Build 15063) (15063.rs2_release.170317-1834)
Processor: Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz (8 CPUs), ~3.4GHz
Motherboard: ASUS SABERTOOTH P67
Memory: 16384MB RAM (DDR3 PC3-10700 667 MHz)
Graphics: NVIDIA GeForce GTX 980

Right now, the databases I analyze in Excel strain my CPU pretty badly (tens of thousands of lines of data, all with complex calculations on top of more calculations). I won't go into details, but I have taken multiple steps to make things more efficient. Anyway, my CPU always runs @ 100% when updating and the updates are taking way too long. Therefore, I was wondering if I could get some recommendations on CPU & MB upgrades. My knowledge of current hardware is limited so I do not know where to begin with a price range but ideally, I would like to see a significant improvement in the processor. For example, looking at the CPU Mark, the i7-6800K is significantly more powerful so something in that price range makes sense (hey, maybe that is even a great option). I also game on the side but given my current CPU seems to handle most games, that has not been a concern of mine.

Thank you!

[David (PassMark)]

Excel is multi-threaded (the newer versions of Excel in any case), but not all calculations can be done in parallel. So you should determine if your spreadsheets are loading all CPU cores of just one core. (i.e. examine task manager while a long calculation is taking place). Also check the RAM usage at the same time.
Also what is your overall budget for the upgrade?

With the answer to these 3 questions, we can make a better suggestion.

[CodenameAter]

Thanks for getting back to me David.

So depending on which computer I use, I have different monitoring software. Regardless, all the CPUs are running @ 100% during calculations, with excel usually taking up about 94% of that. Most of the calculations are SUMPRODUCTS and INDEX-MATCH, which I believe can be multi-threaded since many of them are not dependant on each other.

My RAM typically hovers around 50% when idling and may jump up slightly, but never reaches 100%.

Finally, budget is somewhat up in the air. As I mentioned in my initial post, I have no idea what current CPUs cost for what I want to accomplish. Obviously I do not want to buy something so cheap that the performance increase over my current system is almost unnoticeable. At the same time, I highly doubt I will be able to justify spending $1300 on the CPU alone. Based on what I am seeing online, it looks like some of the mid-higher end CPU/MB bundles are in the $750 range, so something in that range perhaps.

I hope that helps and thanks again for your assistance

[David (PassMark)]

Some desktop options
AMD Ryzen 7 1800X
Intel Core i7-6850K @ 3.60GHz
AMD Ryzen 7 1700
Intel Core i7-7700K @ 4.20GHz

Motherboard selected will depend on the CPU selected.

Also you'll need new RAM, as DDR4 is the new standard with new motherboards. Get a motherboard with 4 RAM slots, so you have the option to expand to 24 - 32GB in the future.

[CodenameAter]

Thank you for the suggestions David!