TheKDub

The stock ones are pretty easy to get off, but are somewhat tricky to get back on. The aftermarket pads I used were even harder to get on (because you've gotta stretch them a bit), but fit great once they're on. Here's a video of how to take them off, clean the headphones, and put them back on. I couldn't find a video of how to put on the HM5 pads, but it's the same concept (just more stretching) as the normal pads.

I've got the DT 770 Pro 80 Ohm and love them. The DT 770s would give better bass. The DT 990s would give a better soundstage. (Should be better for the music you listen to). Just keep in mind with the DT 990s being open back, you're gonna let in more ambient sound and let out more of what you're listening to. Also, if you're not satisfied with the stock earpads, I got the Brainwavz HM5 sheepskin leather pads and they're amazing. They take a little stretching and patience to get on, but they work great.

That sound of "liquid flowing" was likely air bubbles working their way through the loop. They settle out after a while. It's not uncommon for there to be at least a little bit of air trapped in an AIO, and it's generally nothing to worry about.

Then I wouldn't worry too much about it. You could try re-applying thermal paste to see if that helps, but it doesn't sound like that big of an issue.

I wouldn't worry much about it. Idle temps don't matter nearly as much as load temps. As long as it stays below 80c under full load, I'd say it's fine. You could try increasing the pump speed to see if that helps at all. I doubt bending the pins would cause this, especially if you bent them back and the CPU sockets properly.

If you can wait until close to next year before building the PC, then I'd wait for next gen Ryzen. Otherwise, don't bother waiting and just go with 3rd gen Ryzen.

That's very inaccurate. Many components are made in Taiwan, Japan, and Korea, including things like monitors, CPUs, GPUs, SSDs, and RAM. The Wuhan Coronavirus won't have much impact on PC component prices, if any, and if it did, it wouldn't last for long.

I'd go with the 3900X regardless. The 9900K isn't worth the extra $80 (+ however much more for an adequate cooler, which will be probably at least another $90) for maybe a few extra FPS. Next gen Ryzen probably won't be here until late this year, so I wouldn't bother waiting unless you don't really need the PC until close to next year.

What if it's supposed to be there to protect the circuitry? I wouldn't just go scrubbing/scraping off things without much reason (such as cleaning a specific area to fix it, or cleaning corrosion.)

Not possible. Also, SLI and Crossfire aren't worth it (at least for gaming). So few games support it that it's not worth the added cost, and you might end up with more bugs or worse performance because of it as well, since some games react really poorly to SLI and/or Crossfire.

It shouldn't take much force. Maybe as much as you'd use when writing with a pen or pencil, if that.

Isopropyl alcohol if you do. It won't "dissolve" the dust, but it can help to clean it off. Make sure it sits out for a few hours to ensure all of the alcohol (and water) has evaporated fully before re-connecting to any power sources. Just get some canned air and blast the dust away. You can also use a soft bristled brush (think small paintbrush) to help loosen some stuff that's more caked in. I've also used Q-Tips with isopropyl alcohol to remove dust and remnants of spilled soda from electronics before.

3900X is $470. 9900K is $550 ($80 more). The 9900K is only slightly more powerful for single threaded applications, however the 3900X dominates it for anything capable of using more than 16 threads. If you overclock the 9900K, the gap grows a little more, but keep in mind you're looking at over 200W of power draw with it under heavy loads, and even higher if overclocked. The 3900X on the other hand tops out around 150W of power draw. With that added power draw, you're also going to have a ton more heat to deal with. $80 less for 50-100W less

The Ryzen 7 2700X doesn't support PCIe 4.0. Don't worry about it, there won't be a performance difference between the GPU using PCIe 3.0 and PCIe 4.0. For the most part the only thing that can really take advantage of PCIe 4.0's speed is SSDs.

If you're planning on using them for gaming, absolutely not. Crossfire (and SLI) are both essentially dead. Very few games still support it, and the performance gains when they do aren't worth the added component cost, heat output, and power consumption.