Carry on or check?

@BuckGup I'm not an experienced flyer, so I'm torn on that. Do I put it in checked baggage and risk it being messed with or straight up confiscated or whatever they'd do, or put it in carryon and be able to at least explain wtf it is to them?

I'm guessing checked is probably a better idea.

Yeah checked is a much better idea. As long as it's not an actual bomb, laser, or banned item you can bring it. Checked is much more strict and I'm pretty sure the capacitors in a power supply might be an iffy thing. I've flown with GPUs and RC cars stacked full of Lipo batteries and everything was fine for checked. You can always ask the flight security if it is allowed.

@BuckGup Hmmm then the next question is just whether its a good idea period. I've got an older 3rd gen i5 machine waiting in Israel. With my GTX 1070 and a proper PSU, it could be pretty capable. I'd also be bringing a hard drive loaded with and OS and some games, as I won't have wifi there, and the data will be limited and slow.

I don't see anything wrong with it. Just make sure to put padding around it

@BuckGupI'd probably have the GPU in its box with its original padding, with a hard drive snugly in my camera bag. The PSU I'd have looser, as the box for that is oversized. All of this would theoretically be stuffed in with a good few layers of clothing.

Where do you live and where do you need to go? If you're crossing borders you may have problems with customs.

Other than that, if they see electronics or in general objects they can't recognize in the metal detector they'll have you take them out and explain what they are. It's more of a hassle than an actual problem in most countries.

@Sauron Maryland, USA, to Tel Aviv, Israel. 

In regards to your second point, what would they do if it was in the checked luggage?

If it's in the checked luggage you can pretty much bring whatever (as long as it's not drugs or something). In Israel they're pretty strict with their controls though so I wouldn't risk showing up with a graphics card - not necessarily because they'd think it's a bomb, but you may have problems.

@Sauron yep. Which is my worry. Either they see it and ask me about it and understand what it is, or more likely they become uncommunicative asses and interrogate me for an hour. Israelis are not big on politeness or customer service.