#3612
Yeah, you're in a somewhat shitty situation.
You fell for the advertising. 3200 MHz isn't some great achievement for a 2600X. 1800X on launch day, sure, but with a 2600X (which already supports 2933 JEDEC, without XMP) and a mature BIOS it's really not some great achievement anymore. That's the least of your worries though.

Your motherboard is a dead end. Even upgrading to a 3600(X) wouldn't do anything. You'll run into the same problem as with overclocking the 2600X. It's simply a race whether your CPU or VRMs will hit their temperature limit first. A cooler won't help if you don't seriously beef up the airflow inside the case to help the VRMs. Even then it'll be a struggle.
Better thermal paste is a meme. 0.2 °C less won't fix a heat problem.

Either way you should probably be more specific about it "not cutting it". I mean you can definitely get the 2600X to 4.2 (or at least close enough) and have it stay there, it's just a matter of how painful and expensive it'll be. But will that fix your problem? You're saying it's already above 4.0, sometimes even at 4.1 so getting it to 4.2 would mean less than 5% more fps. I doubt that's what you're looking for.
Coming from a 2600X in a suboptimal configuration (bad cooling, bad VRMs, slow RAM) does mean that a 9600K @5.0 is a much bigger ugprade than if you were running let's say a 3600 under ideal conditions but I've still got no idea if it would be enough. How much more fps do you want/need? This is further complicated by how sensitive TF2 is to RAM latency. You can't afford cheaping out on the RAM or you'll risk losing half of your potential gains, but at the same time your budget is kind of forcing you to cheap out on the RAM if you want a 9600K.

Regarding the monitors: What are you looking for? Is the only criterion that it must cost between 400 and 500 CAD or do you have actual requirements? Why would you even go by price instead of by features/performance? Do you expect there to be some magic ranking that can tell you which is the absolute best monitor in a certain price range?

Which Ryzen CPU are you switching from?
Why not a 9600KF?
You're not going to get to 5 GHz with a budget mobo. Not like Z390 budget mobos are a thing anyway.
On the other hand without going trash tier with unheatsinked VRMs (have fun with those) I can't find any Z390 mobos for less than 200 CAD which places 9600K(F) + mobo + RAM + cooler for 600 CAD firmly in the "not happening" category.

Also I wouldn't recommend buying a 9600K(F) which uses thermal paste two weeks before the 10600K is released, which is supposedly based on the 10 core Comet Lake die and therefore soldered.

The way I see it you've got 2 problems:
1. For streaming you'd definitely want to choose the 6c/12t 10600K over the 6c/6t 9600K.
2. You can't even afford a 9600K if you want a good mobo, RAM and cooler. It'd be a bit pointless if you cheap out and end up getting all of 10% more fps for 600 CAD.

But you're not paying for a LAN you're paying for LAN sustainability. What's more sustainable than a LAN that costs absolutely no resources because it's always one season away and never actually happens? That's the only type of LAN that can be sustained indefinitely. You're just paying sigafoo for inventing that glorious concept.

#3606
See #3607.
Honestly I'm still not sure which "monster hunter (ultimate)" you mean.
SSD is just about how fast an SSD you "need"/want. WD Blue SN550 1TB seems to be a bit cheaper than the 660p right now so that's fine. Anything significantly faster and therefore more expensive would push you over 900£.

Hope you're not in a hurry, at this rate we might be here for a while.

When did you plan on building it? If you can wait until the Comet Lake launch at the end of May do so.
Just so you've got something to work with in case you are in a hurry, assuming you'll use GPU encoding for streaming:
https://uk.pcpartpicker.com/list/GXGHL2
https://uk.pcpartpicker.com/list/RY7ZPn
Just as a sort of baseline. Especially the SSD is just a suggestion, nothing wrong with 256/512 GB SSD + 1/2 TB HDD or even 1 TB SSD. Didn't check the mobo QVL (just google it) for the RAM, you should probably do that for the 3600 build, it tends to be a bit picky. 3600 MHz, CL16 (again, google) if you can find a cheap one but it's not really necessary.
I've got no idea which build is better. 3600 should be a tiny bit better for Monster Hunter, but you'll be limited by the GPU anyway. TF2 no idea. 9600 is higher clocked but with the slower RAM I'd have to guess which one is faster. Could get 3600 MHz RAM for the 9600 as well but because Intel are bastards they limit you to 2666 MHz unless you buy a Z370/Z390 (overclocking) motherboard. 30 quid more for the mobo and another +30 for the RAM and it's not really working out with the budget anymore. Dropping down to a cheaper GPU and the 3600 build definitely wins in Monster Hunter. Could get a 9500F instead (cheaper) to make it work but that's lower clocked so I'd have to guess that it's still faster in TF2 than the 3600 but only by a tiny bit (and it's still more expensive than the 3600, both the CPU itself and the mobo). Also getting an overclocking mobo for a locked CPU that can't be overclocked is weird as fuck.
Could also throw the 3600X into the ring, but again it's only a tiny bit faster so it doesn't really feel like it'd be worth it. Yeah, best performance <900£ and all that but I don't know what you're going to do with storage situation, different case maybe (not that small tbh even though it's µATX, mostly there to see how the budget works out), maybe a different PSU, RAM that's actually on the QVL is probably going to be a bit more expensive as well and then the budget's already gone and the 3600X doesn't fit anymore.

Choices, choices...

Not very helpful I know, but I'm not really feeling like weighing the pros and cons right now because if you are able to wait I'd have to redo it all after the 10600 is available.
Also forgot how many fps you want in Monster Hunter (which one exactly anyway?) and on what resolution.

I don't think you can buy from pcpartpicker.
Streaming yes/no?

EDIT:
A new page appeared between me reading and me replying. Not the best response time, I guess. Might be getting old.

A used GPU might be an option.
9600KF would be nice, but only if you can get a cheap cooler as well.

Don't get an H310 board, they're usually shit and 2 RAM slots is going to come back to haunt you when you realize that 8GB isn't quite enough for everything.
There's no reason to go for a SATA SSD when you can get NVMe.
You're really not in a position where you can drop 80$ (16% of your budget) on a fully modular 600W PSU for a 300W build just because you feel like it. At most semi-modular.
https://pcpartpicker.com/product/8P7CmG/evga-bq-500w-80-bronze-certified-semi-modular-atx-power-supply-110-bq-0500-k1 or
https://pcpartpicker.com/product/FQ648d/corsair-power-supply-cp9020101na

PCPartPicker Part List

CPU: Intel Core i5-9500F 3 GHz 6-Core Processor ($88.00)
Motherboard: Gigabyte B365M DS3H Micro ATX LGA1151 Motherboard ($74.98 @ Amazon)
Memory: Patriot Viper Elite 8 GB (2 x 4 GB) DDR4-2666 Memory ($37.99 @ Amazon)
Storage: HP EX900 250 GB M.2-2280 NVME Solid State Drive ($44.99 @ Amazon)
Video Card: XFX Radeon RX 570 4 GB RS XXX Video Card ($121.98 @ Newegg)
Case: Cougar MX330-G ATX Mid Tower Case ($46.98 @ Newegg)
Power Supply: SeaSonic S12III 550 W 80+ Bronze Certified ATX Power Supply ($54.99 @ B&H)
Monitor: BenQ ZOWIE XL2411P 24.0" 1920x1080 144 Hz Monitor ($199.00 @ B&H)
Total: $668.91
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2020-04-14 13:42 EDT-0400

Then he should definitely wait until the end of May or whenever the Intel 10th gen launch happens. Even if he doesn't end up buying any of the new CPUs it can't hurt to wait for lower prices for the old ones.

Anything more specific than "modern RPG games"?
Also when is he going to build it?

So you think that when a game doesn't run silky smooth on a 5 years old CPU an extra 10% are going to save you?
Don't get me wrong, I wouldn't cheap out on the mobo to block any attempts at overclocking, but in the case of Intel paying 50€ extra for a K CPU, 50€ extra for a Z mobo and another 50€ for a cooler now just because maybe in 5 years they might actually be useful...

#3592
See #3593.

Also:

That's not how it works. If you need to overclock to get the performance you want you have to do it immediately. If you don't need to then you never need to. What could possibly a the reason that you need to overclock, but only after 6 months, if you're still playing the same game?

#3588
B365 is limited to 2666 MHz RAM.
MCE or whatever it's called for that mobo should get you a bit more performance at the cost of increased power consumption. I'm not sure how much B365 is allowed to fiddle with the TDP though, so it might not be nearly as much as on a Z mobo that can just set the power limit to 4096W, effectively removing it.
Also since the max all core turbo is 3.9 you will get that with 5/6 cores active and 4.0 with 2-4 cores. You only get 4.1 with a single core and even TF2 uses more than 1.

Intel 10th gen announcent 27th of April, launch 30th of May, afaik. Not sure if you're willing to wait.

I'm also not convinced that the 9400F is the ideal choice. A 3600 would allow you to actually use 3200 (or higher) RAM and with that plus the fact that even with the stock cooler a 3600 should boost to 4.1 all core, more for single core and probably slightly more for everything with an H7, I doubt that the 9400F would be any faster in games. For DAW 12 threads vs 6 threads means it won't even be close.

#3589
2 sticks of RAM, always. With a mobo with 4 slots you're not even sacrificing any upgradeability so throwing away half the bandwidth by not using Dual Channel makes no sense.
The 1600 AF isn't exactly the same as the 2600, it's lower clocked, but it is a cheaper and only marginally slower option. Think 2600X vs 2600. The 1600 AF is rarely sold for the 85$ MSRP, usually 100$ instead, and the 2600 is down to 125$ from 200$ MSRP but those 25$ could still solve your budget problems.

The goto are 3600 CL16 kits that work out of the box, as shown by the QVL (list of memory the mobo manufacturer tested). The gold standard among those are specific chips (Samsung B-Dies) which play a bit nicer with the Ryzen memory controller and oc a little better.
https://benzhaomin.github.io/bdiefinder/
The "lesser" version with 16-19-19-39 timings are around 120£, the better 16-16-16-36 around 130£ if you're lucky.
The rare and elusive 15-15-15-35 (I only know of the F4-3600C15D-16GTZ) should be around 150£.
CL14 is where the price gouging starts.
Now I'm not saying that a lot of these 3600 CL16 kits won't be listed at 200£ (or even 250£, yes I'm looking at you, Corsair), just that the cheapest of them will be much cheaper.

Yes, if it can handle 3600 CL14 and 4266 CL19 it should also be able to handle 3733 CL15. Yes, that should be better than 3600 CL14 for Ryzen.

You can edit posts, no need to post twice in 2 minutes.
If all you wanted was 3733 MHz CL14 it would've been a lot easier to start with a 3600 MHz CL15 kit that's already at 8.33 ns with only 1.35 V (-> some room for higher voltage left) instead of trying to force a kit that needs 1.45 V for 4400 Mhz CL19 = 8.64 ns into that.

Not that it really matters all that much. IF dominates the latency anyway so even 3733 Mhz CL15 would win against 3600 Mhz CL14 in both latency and bandwidth. I'm not entirely sure what you're trying to achieve.

#3577
It's 4400 or 4266 MHz Cl19, that's 8.64 or 8.91 ns latency.
3600 MHz CL14 is 7.78 ns, 3733 MHz is 7.50 ns.
Why are you surprised that that's not stable?

Also you maybe should've checked the QVL and/or manufacturer's website.
https://viper.patriotmemory.com/products/viper-steel-ddr4-performance-memory-ram-viper-gaming-by-patriot-memory

#3578
Nope. 4400/4266 CL19 or 2133 CL15. 4400 CL15 would be insane.
https://assets.website-files.com/5cdb2ee0b102f96c3906500f/5dd6b314aa0dd278b0b6efc6_PVS416G440C9K%20Sku%20Sheet_Copyable_062819.pdf

1.45 V for 4400 Mhz CL19.

No.
Case closed.