Since Ninjatrader 8 has so low sys reqs (
source), that isn't needed to consider here, which leaves gaming. Currently, best CPU to go for gaming is i5-9600K due to it's good price to performance ratio. Core i5 also has 6 cores/threads which is enough for any game out there and it can handle game streaming as well (if you're into that). Core i7 and Core i9 are good for workstation PCs where plenty of cores/threads are needed.
As far as MoBo goes, pick the one that you like most feature wise. For i5-9600k, i7-9700K and i9-9900K, any 300-series MoBo (B360, H370, Z370 or Z390 chipset) with LGA1151 socket will do. B360, H370 and Z370 chipset MoBos need the latest BIOS though.
For RAM, brand doesn't make much difference. G.Skill is good and so is Corsair. Though i'm using Kingston RAM in my PCs.
So, here are 2x build upgrade suggestions for you:
1) Budget upgrade (which i'd pick):
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel - Core i5-9600K 3.7 GHz 6-Core Processor ($264.89 @ OutletPC)
CPU Cooler: ARCTIC - Freezer 33 eSports ONE (Black/Red) CPU Cooler ($37.49 @ Amazon)
Motherboard: MSI - MPG Z390 GAMING EDGE AC ATX LGA1151 Motherboard ($189.89 @ OutletPC)
Memory: Corsair - Vengeance LPX 16 GB (2 x 8 GB) DDR4-3000 Memory ($109.99 @ Amazon)
Storage: Samsung - 850 EVO-Series 250 GB 2.5" Solid State Drive (Purchased For $0.00)
Storage: Western Digital - Caviar Blue 1 TB 3.5" 7200RPM Internal Hard Drive (Purchased For $0.00)
Video Card: MSI - GeForce GTX 970 4 GB Video Card (2-Way SLI) (Purchased For $0.00)
Video Card: MSI - GeForce GTX 970 4 GB Video Card (2-Way SLI) (Purchased For $0.00)
Case: Cooler Master - HAF X ATX Full Tower Case (Purchased For $0.00)
Power Supply: SeaSonic - FOCUS Plus Gold 750 W 80+ Gold Certified Fully-Modular ATX Power Supply ($109.99 @ SuperBiiz)
Total: $712.25
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-04-08 11:47 EDT-0400
Few words
Like said above, for gaming i5-9600K is best CPU, so put one in.
Also upgraded CPU cooler from (relatively) poor performing Hyper 212 Evo to Arctic Freezer 33 eSports One. Besides having better cooling, new CPU cooler also matches your black & red theme.
MoBo is one of the two you picked out.
For gaming 16GB of RAM is more than enough, so put 2x 8GB 3000 Mhz RAM in. RAM is normal profile and with black heatsinks. You can pick red heatsinks as well if you want RAM to stick out some more (
pcpp).
And lastly, i replaced your old and low build quality Corsair PSU with much modern and good build quality Seasonic PSU.
2) No budget limitation (overkill in many ways):
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel - Core i9-9900K 3.6 GHz 8-Core Processor ($509.99 @ Walmart)
CPU Cooler: be quiet! - Dark Rock Pro 3 67.8 CFM Fluid Dynamic Bearing CPU Cooler ($119.89 @ OutletPC)
Motherboard: MSI - MPG Z390 GAMING EDGE AC ATX LGA1151 Motherboard ($189.89 @ OutletPC)
Memory: Corsair - Vengeance LPX 32 GB (2 x 16 GB) DDR4-3000 Memory ($199.99 @ Amazon)
Storage: Samsung - 850 EVO-Series 250 GB 2.5" Solid State Drive (Purchased For $0.00)
Storage: Western Digital - Caviar Blue 1 TB 3.5" 7200RPM Internal Hard Drive (Purchased For $0.00)
Video Card: MSI - GeForce GTX 970 4 GB Video Card (2-Way SLI) (Purchased For $0.00)
Video Card: MSI - GeForce GTX 970 4 GB Video Card (2-Way SLI) (Purchased For $0.00)
Case: Cooler Master - HAF X ATX Full Tower Case (Purchased For $0.00)
Power Supply: SeaSonic - PRIME Ultra Titanium 750 W 80+ Titanium Certified Fully-Modular ATX Power Supply ($199.99 @ Amazon)
Total: $1219.75
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-04-08 11:57 EDT-0400
Few words
Compared to the build above, everything got changed, except MoBo. Starting off, there's i9-9900K in there with it's 8 cores and 16 threads.
Since Core i9 is far more powerful than Core i5, only the best of air cooling would do and so, put in Dark Rock Pro 3, which is only few degrees short of the king of air coolers (NH-D15) while looking considerably better.
RAM also got an upgrade in form of 2x 16GB 3000 Mhz. Though, since Dark Rock Pro 3 is so big, only normal-profile RAM fits under it, hence why there's Corsair RAM here as well and not G.Skill. Also, even if you'd go with G.Skill RGB RAM for eyecandy, Dark Rock Pro 3 would hide the RAM entirely, making RGB RAM pointless. Note: install RAM before installing CPU cooler, it's easier this way.
And lastly, put in the best PSU money can buy at current date: Seasonic PRIME Ultra 750 (80+ Titanium). The Seasonic Focus+ 750 (80+ Gold) in above build is also good but PRIME series is the flagship of Seasonic and only PSU series in the world that comes with 12 years! of warranty. Oh, Focus+ has 10 years of warranty. (All my 3 PCs: Skylake, Haswell and AMD are also powered by Seasonic while i have the PRIME 650 (80+ Titanium) unit in Skylake build. Full specs with pics in my sig.)
With Core i9 and 32GB of RAM (with possibility to upgrade to 64GB), that PC is more like a high-end workstation PC (ideal for video rendering), rather than gaming PC.