Schrodingers Kat

If your just playing games I suggest you rebalance the CPU and GPU, my suggestion is a Ryzen 5600x and a 3070 instead of what you selected as it will get you better FPS in all games for the same money. Most B550 mobos will be fine to go along with it, the msi tomahawk being a good place to look.

You can get the new PSU working with just the graphics card if you short the 24pin with a wire (google how) if you really want to try. If the HP motherboard has standard connections like 24 pin for the mobo etc (which it may not being an OEM pc, some of them have proprietary connections for their own custom cheap mobos), then you could spend the time and change the whole psu over to the new one while you wait. I dont think any other part of the system can physically harm the GPU so you might be good to try it. You might have to dive into the BIOS and change the video output to the new card. Then last of all is the drivers which can play funny on system hardware they're not made for, but its worth a shot. All the other problems like PCIE lane allocation and such don't matter too much as the performance will still be decent-ish and severely held back by the CPU regardless. Let us know how it goes if you try it for future help with other builds.

Ignoring the huge disparity between CPU and GPU performance with the 3080 some issues will be the too small PSU (300W wont likely be enough and may not be on the right rails and also probs wont have 2 spare 8 pin connecters, even if the GPU is CPU throttled hard), physical size in the system (may not actually fit in the case w/o modding it), and there might not be an extra PCIEx16 slot length for the card to slot into (you'll have to open up and see yourself). There might be more problems but that's at least a few to try and solve first. Probably best just slowly building the system and not using the parts until you have them all. You wouldn't want to risk that valuable rare card with getting incorrect voltage or something else that could damage it.

I wouldn’t think it has anything to do with the memory on the card, but if it’s faulty then yeah maybe that could cause it. Check to see what voltage states the gpu is running at and if it lowers to a lower voltage when under load (can be seen in afterburner). If it’s lower than a full load then something might be wrong with the gpu itself or the bios on the card. Had an issue similar to this on my 980ti where it would lock to a low voltage so the card would never perform well and I fixed it by flashing a new gpu bios. As far as checking the psu the only way I can think of is testing a different psu, or changing the slot on the psu that the power cables are plugged into. If it’s one dodgy power rail then it could be fixed, but if your psu pcie power slots are all on one rail then only a different psu would show a difference.

Some random ideas, have you checked if the gpu is overheating (so maybe a faulty fan or something)? Also it might be bottlenecked elsewhere than the gpu, so check the storage, cpu and ram usage while your trying to game and see if one of them is stuck maxed out for some reason (also temperature for the cpu). Then maybe see if your card isn’t getting the power it needs meaning the psu might be shot. That’s all I can think of. Edit: gpu might be broken as well. Obviously.

Overall doesnt look bad, try emailing mwave to see if they'll ensure the bios has been updated to ensure compatibility with the 3600. And their storefront might have the ability to do it for you too. For the build you could push for faster ram (3200mz) and you could try for nvme for the system drive, with either a hdd or a cheap ssd for the mass storage. Neither are required but could be a good way to spend the rest of the budget.

Some games have issues running on four threads, so you shouldnt have any of those sorts of issues with the 3600. GamersNexus has some videos on similar problems, but the issue is always related to limited thread count, not so much the power of the cpu itself. Example is when he gets the 9700k stuttering in his video.

Price depends on where you are, but as far as cooling goes air cooling can do well enough for the 9900k but not perfect. My 9900k is under a NHD-15 and it barely keeps up with a 5ghz overclock (but its hot where i live so doesnt help). I personally prefer not to have it under water for fear of leaks

Honestly for just gaming a ryzen 3600 would be fine (unless you have a real need for high frame rate gaming 144+) while also providing good overall performance and a good platform with modern features. Get some decent 3200mhz memory and call it a day

The i3 will outperform the 1200 in gaming (not by a large amount mind) but the physical 4 cores compared to the 2 cores w/hyper threading can make a difference in other uses around the pc. The bigger choice is the gpu. If getting the 1200 allows for a better gpu than what you could afford with the i3 then get the 1200 and the better gpu. If all else is equal and the gpu wont change between each cpu, and gaming is your number 1 priority, then the i3 would be the choice. Something else to take into consideration however is the b350 board for ryzen will be the same socket used for a while, so its possible to upgrade the cpu to the 1600's successor for example in the future, whereas on the intel platform your locked with the cpu you buy for the life of your platform.

There's a lot of personal preference when picking budget phones, like what you value more in a phone. The moto E series were a good start for stock android with decent performance with ok hardware. Some of the Chinese brands have better hardware for the price however they have their own skins on android and some (like myself) find them more annoying than they're worth. Really depends on what you consider budget though. Sometimes old flagship phones are the better choice if you can afford them.

AnandTech has a rough formula for working out ram performance, which is Speed/Cas in mHz. Eg 2400mHz at CAS 15 = 160. However really just aim for what you can afford within your build, minimum should be 2400 mhz at any timings unless its a really budget build. After that aim for 3000 or 3200. Remember any overclocking mobos will allow for overclocking ram also so you can somewhat help middling ram timings later with an overclock at higher ram voltage.

Not sure what your currency works out to be but the sennheiser hd 558 is an excellent start to open headphones. Edit: The 559s are on sale on amazon atm so theyre well within your budget and are very similar to the 558s.

^ +1 however the g4560 will beat the 1200 in gaming only so aim for that over ryzen if thats your only objective.

The only reason to upgrade the H100 would be if its 3+ years old, and even then if its not making extra noise then its working fine. As for recommendations the kraken x62 is pretty pricey so id also throw the H115, or an older H110 for cheaper if you can find one. For GPU if your playing 1080p a 580 (out of stock atm) or a 1060 6g will do you well, however dont have a massive gain over a 970 tbh. Youd have to step to a 1070 or upward to see a large gain.