The best upgrade would be CPU. Since your i7-3770 is the best LGA1155 socket CPU, you should go with new MoBo if you want to have better CPU.
Here's the best you'd be looking at.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i7-7700K 4.2GHz Quad-Core Processor ($344.99 @ SuperBiiz)
CPU Cooler: be quiet! Dark Rock Pro 3 67.8 CFM Fluid Dynamic Bearing CPU Cooler ($80.99 @ SuperBiiz)
Motherboard: MSI Z270 GAMING M5 ATX LGA1151 Motherboard ($199.99 @ B&H)
Memory: Corsair Vengeance LPX 32GB (2 x 16GB) DDR4-3000 Memory ($206.99 @ Newegg)
Total: $832.96
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-01-17 21:24 EST-0500
Few words.
Put in the best CPU from Intel's latest CPU family, Kaby Lake. CPU is K-series so you can OC (overclock) it and get more juice out of it if you like.
comparison between i7-3770 and i7-770K:
http://cpu.userbenchmark.com/Compare/Intel-Core-i7-3770-vs-Intel-Core-i7-7700K/1979vs3647
Since Intel's K-series CPUs don't come with stock cooler, added one of the best air coolers that fits into your case.
Here's a reason why i picked this CPU cooler:
http://www.tomshardware.com/reviews/best-cpu-coolers,4181.html
Since i7-7700K uses LGA1151 socket, picked Z270 chipset MoBo for it that uses much faster DDR4 RAM. MoBo has plenty of handful features, including CPU OC and support for RAM speeds up to 3800 Mhz.
specs:
https://www.msi.com/Motherboard/Z270-GAMING-M5.html#productSpecification-section
Sadly, i7-7700K supports only DDR4 RAM and you can't reuse your DDR3 RAM. So, went on and put in 2x 16GB (32GB) of DDR4 RAM that you can OC and run at speeds up to 3000 Mhz. MoBo has total of 4 RAM slots and with this upgrade, you're left with 2 free RAM slots for future RAM upgrade.
You can remove the CPU cooler i added and reuse your old CPU cooler but the cooler i added offers far grater CPU cooling performance than your Thermaltake.
Here's also a 2nd upgrade path to take that costs far less money.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor ($334.49 @ SuperBiiz)
Motherboard: MSI Z97-GAMING 5 ATX LGA1150 Motherboard ($137.37 @ OutletPC)
Total: $471.86
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-01-17 21:35 EST-0500
Also few words.
This time went with the best Haswell family CPU from Intel. i7-4790K is the best CPU that supports DDR3 RAM. CPU is also K-series so you can OC it.
comparison between i7-3770 and i7-4790K:
http://cpu.userbenchmark.com/Compare/Intel-Core-i7-3770-vs-Intel-Core-i7-4790K/1979vs2384
Added LGA1150 socket MoBo that is Z-series, so you can OC your CPU and reuse your DDR3 RAM.
specs:
https://www.msi.com/Motherboard/Z97-GAMING-5.html#hero-specification
With this upgrade path, you can reuse most of your parts (including CPU cooler) while keeping the upgrade cost minimal.
For a bonus, here's a comparison between Haswell's i7-4790K and Kaby Lake's i7-7700K:
http://cpu.userbenchmark.com/Compare/Intel-Core-i7-4790K-vs-Intel-Core-i7-7700K/2384vs3647
And for a 2nd bonus, a comparison between Hasewell build (as a base) and Kaby Lake build (as an alternative).
(For your use, the work criteria should be as high as possible.)
Userbenchmark PC Build Comparison
Baseline Bench: Game 107%, Desk 87%, Work 68%
CPU:
Intel Core i7-4790K
GPU:
Nvidia GTX 1070
SSD:
Samsung 750 EVO 250GB
HDD:
Seagate Barracuda 7200.14 1TB
RAM:
HyperX Fury DDR3 1600 C10 2x8GB
Alternative Bench: Game 110%, Desk 96%, Work 77%
CPU:
Intel Core i7-7700K
GPU:
Nvidia GTX 1070
SSD:
Samsung 750 EVO 250GB
HDD:
Seagate Barracuda 7200.14 1TB
RAM:
Corsair Vengeance LPX DDR4 3000 C15 2x8GB
Facebook
Twitter
Instagram