The following information comes from NeoGAF user 10k, who has been verified by various sources. I don't want to misconstrue any of his info, so I'm going to share his NeoGAF post in its entirety.

Ok, this is my first time posting any kind of rumor, leak, or insider information, whatever you want to call it. While I believe the info to be true, things can always change at the last minute and then I look like an asshole who lied. I have more than one source and this post will basically contain things I've heard, conversations I've had with people in the know (other insiders, devs, writers, etc). To make this easier, I think I'll do a tiered rumor ranking, where a T1 (Tier 1) means one source told me this, T2 means two, T3 means three, and T4 means at least four sources or more told me or others the same thing. So T4 rumors have multiple sources and are likely more credible than a T1, but that doesn’t necessarily mean a T1 is false. The bolded parts will be the rumor, the text after it will be additional info mixed with some of my opinion, and the sources thoughts.

Also, while I was writing this short essay I asked my new sources about the May 9th NX reveal date, they said they'd look into it.

Remember, I'm no journalist or english major :p

T4 Rumors

The NX will be more powerful than the PS4. "By a noticeable amount". From the CPU, to GPU, to RAM. Sources don't know the clock speeds, or memory type or amount of memory. But if the CPU is 15-30% stronger than PS4 as alluded to by LCGeek, than the GPU would need to match that bump in order to not bottleneck (Nintendo hates their bottlenecks).

The Wii U Remasters. 100% confirmed Smash Bros 4 will come to NX, no word on if you can play with Wii U players.

Zelda is 100% confirmed and not really big news :P

Now here is where things get interesting. One source said 100% for sure Mario Maker was coming to NX. Another source said 50%. Why 50%? Well, they can confirm it's in development, Nintendo is struggling to transfer over player data and doesn't want all courses to be lost. Hell, courses are being mysteriously deleted on Wii U already lol.

The fourth remaster is Splatoon. This one was given 50% chance from two sources and 99% from one source lol. The reasons again are, Nintendo is struggling to transfer all player data and make it cross-compatible with Wii U players as well. It is in development though. They should have all he DLC included.

So, Zelda and Smash for sure, Mario Maker and Splatoon maybe. If Nintendo can't get it working they may scrap it.

Smash is rumored for launch along with Zelda (day or window wasn’t specified). Not sure on Mario Maker or Splatoon.

What's interesting about this is Splatoon and Mario Maker heavily use touch controls and motion controls. While I certainly expect the NX controller to use gyroscope and accelerometers (since even the DS4, Wii U gamepad, Wii remotes and 3DS use it) this may indicate that there will be a screen in the NX controller. None of my sources indicated troubled development of splatoon and mario maker were controls related, so either it has a screen controller or the second screen support hinted at by the reddit leaker in the OP was right and there will be some kind of optional screen controller or smartglass like features.

T2 Rumors

NDA's are tight as hell. This one is obvious. But I just wanted to add to it. While fellow posters like Rosti have indicated how heavy they are, my own sources and people I don't even know have warned me privately to watch what I post here (this was all within the last couple of hours lol). One source said they know more Nintendo hardware people than software people, yet the only leaks they've been able to get is on the software side. Not a peep from the hardware guys.

I even had people asking what the contents of my post were going to be, if names, job positions, marketing budgets (lol) were going to be posted. A lot of people got very worried, including my sources, the fear of Nintendo is real. They are cracking down. The fake leaks aren't helping either.

As someone who just started snooping for NX info and asking questions out of general curiosity for being a fan, I wasn't expecting this much info over the last two weeks or so. But, now that I am, I want to gain my sources respect and so I didn't want divulge their identity or even reveal their gender. I hope this post has gained their trust, and know that their ID's are safe and sound with me.

T1 Rumors

NX SDK's are out there right now and my sources can confirm dev's have them, so don't worry too much about when you hear stuff like nobody has a dev kit yet.

The NX is easy to port too. This is big because Nintendo consoles have usually been hard to develop or and only mastered by Nintendo's internal teams. Apparently, some dev's are having no trouble porting current gen games over. It's a quick process and dev's seem to be happy about it.

The NX architecture is under NDA but is highly speculated to be x86. I disagreed with them on this but they made some excellent points about how porting from ARM to x86 (handheld to console) and x86 to x86 (current PS4 and XB1 games to NX) is very easy, while it's a bit more tricky to go from x86 to ARM (console to handheld). It certainly matches what the reddit leaker posted.

Based off my high school programming skills and some research, it seems like x86 to ARM does require more work, x86 is 64-bit and ARM is 32-bit. But any decent compiler supports 64-bit math on ARM. The dev's mainly recompile the code into ARM, and then the integer values get changed, and fix any errors that come up, recompile again, see if it works, rinse and repeat. It's not as important or inefficient as people think, especially for larger devs. Besides, ARM is heavily supported and the more worked on architecture. So don't get too focused on if it's x86 or ARM. In the end, as long as it's not shitty PowerPC (Nintendo, please, no) it'll be fine. It won't be the reason Nintendo won't get third party ports, if anything, NX sales will.

One thing that contradicts x86, and this is an indirect source, but a coder who works specifically for Nintendo laughed off GAF's focus on x86 and how we know nothing. Please don’t go looking for them, DetectiveGAF, let them keep their job. So, that, combined with ARM likely being in the handheld, makes me believe the NX will use ARM. But like I said, at the end of the day it doesn't really matter.

Nobody knows anything about the handheld. At least, not any of my sources or their sources. Not even sure if NX refers to the handheld as well or if that has a different codename. It's speculated that it will still get some exclusive games, but won't get many console games downported (referring to the shared games library) while the console could theoretically play them all (maybe lending support to x86 and ARM inside the NX, having the handheld guts inside, but that sounds very expensive and I doubt it). The console seems to be the main focus of Nintendo right now and the New 3DS, along with the 2016 lineup of 3DS, has afforded them that luxury.

I hope you enjoy this post and it provides lots of healthy discussion. I told you it wasn't major news, but you got hyped anyways. It's my first time doing this and it was fun, and sorry if it took awhile but verification and clarity were important to me.

Remember, grain of salt.