You know you can just backup your config before using -default?

SSDs in general are worth it. I'd go for a slightly newer and faster SSD.

2133 or 2400 isn't what you should worry about. Timings and Dual Channel are more important. Single Channel/Stick means you're essentially only getting half the bandwidth you could get. I'd change the mobo to one with 4 slots (e.g. VDH, otherwise the same, but there's other options) so you can still add more RAM later if you want to.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Pentium G4560 3.5GHz Dual-Core Processor ($79.44 @ OutletPC)
Motherboard: MSI - B250M PRO-VDH Micro ATX LGA1151 Motherboard ($64.99 @ Amazon)
Memory: GeIL - SUPER LUCE 8GB (2 x 4GB) DDR4-2400 Memory ($64.99 @ Newegg)
Storage: SK hynix - SL308 250GB 2.5" Solid State Drive ($93.88 @ OutletPC)
Video Card: Zotac - GeForce GTX 1050 2GB Mini Video Card ($109.99 @ SuperBiiz)
Case: Thermaltake - Versa H21 ATX Mid Tower Case ($35.99 @ SuperBiiz)
Power Supply: Corsair - CXM 450W 80+ Bronze Certified Semi-Modular ATX Power Supply ($54.99 @ Newegg)
Total: $504.27
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-08-08 06:59 EDT-0400

Not if you win.

Yeah, if you don't want to wait any longer you can just decide on the mobo by getting whichever is in stock first.

Yes, cooler is sorted out, thermal paste is included.

I won't judge mobos based on the number of LEDs and like I said there are no reviews yet.
The cooler you linked is not the TR4-SP3 version.
The case will work.

Yes, any of those mobos would work.
RAM should be 4 sticks, other than that it can be exactly the same.
You'll need a different cooler, TR4 is physically larger than any cooler available so they wouldn't cover the whole CPU.
There's a list https://www.amd.com/en/thermal-solutions-threadripper but it's not complete.
I generally don't recommend Aios. The Hyper 212 and Freezer 33 aren't particularly impressive so if you can afford it I'd go with an NH-U12S or NH-U14S, TR4-SP3 version, http://noctua.at/en/products/cpu-cooler-retail unless something better is released very soon.

The PSU should be fine, I couldn't find any better PSUs with more appropriate wattage in that shop, 750 or even 850W are overkill even for an 1950X + 1080 Ti.
Also since I just noticed it in the pcp list you used the old CX850M (green) which is quite a lot worse than the new one (grey), don't mess that up when you're actually ordering it.

Ok, just making sure. Another 4 cores extra is obiously nice.

Yes, only TR4.

How are reviews with benchmarks that take days to run available on launch day? Just because you can't buy it yet and shops don't have it in stock yet (see your link) doesn't mean review sites don't have it already.
At this point most reviews are actually done and everyone is just waiting for the NDA date.

#2486
Are you sure you can afford the 1950X? When we did the math the worst case for the 1920X was just about affordable, but I haven't looked at Danish preorder prices yet.
TR4 mobos won't be cheap.
I can't recommend any mobos yet since there's neither prices nor reviews, because they haven't been released yet either.

#2487
Programs that benefit from >16 threads / >8 cores?
Trying to get rid of money?
Needing the largest CPU available (and I do mean physically largest)?
Idk, you decide.

They paid good money for that name so they're going to use it and they're going to make sure you know it's owned by BenQ now.
Also haven't you heard, twice the brandnames means it's twice as good.

2015 MacBook Air should actually be TB2.
https://egpu.io/forums/mac-setup/pcie-slot-dgpu-vs-thunderbolt-3-egpu-internal-display-test/
Scroll down to 2.1
Not completely terrible, but obviously you move down essentially one GPU class.

I don't think it's going to matter much when you're stuck with a 1.6 GHz CPU.

A 400$ build is doable with used parts. I mean you can do this https://pcpartpicker.com/list/fXNDRG with new parts. Used monitor, cheaper HDD and a 1050 Ti would be within budget.

This isn't about multitasking. You don't need a CPU with 16 threads to have spotify running in the background.
Are you actually going to run a program that benefits from >4 threads/cores?

So is it for <=4 threads or more?

Did you even read the error message?
Your problem is not the Steam folder. Neither are other games' files. That's why the update just fine.
Fucking read it.
It says "tf\resource\tf_brazilian.txt" is your problem. Of course that only affects TF2.

The error message says it's the file privileges.
They might not care that you don't think they are the problem.
In fact I'm pretty sure they give absolutely zero fucks about your opinion.