So first off, Nvidia is lying, the mobile GPU X1 is a 10watt apu that does 512GFLOPs not 1TFLOP, they use this number because the X1's FP16 peak performance is 1TFLOPs, however this is half precision, they also note that FP32 peak performance is 512GFLOPs, which is single precision and what everyone is noting when they talk about performance.
That was a 10 watt part, Nintendo will need a part under 3watts. Looking at AMD mullins, we find a 128GFLOPs part on 28nm @ 500mhz using only 2.8watts. Perfect, now Nintendo will be using 14nm most likely, because AMD will be offering it in 2016 thanks to samsung and global founderies. This could mean 256GFLOPs at ~3watts. Great, that is more powerful than Wii U's GPU which is 176GFLOPs, and if Nintendo's handheld is 480p or 540p (my preference as this is 1/4th of a 1080p screen and thus goes 4x further) you have a handheld that can perform alongside a much more powerful console (say ~8x more powerful) giving the console 1080p @ 60fps (16CUs @ 1GHz for 2TFLOPs of performance) and the handheld 540p @ 30fps displaying the same scene roughly. you'd only need 4x the memory, especially if it's faster, so 2GB in the handheld (like Wii U) and 8GB in the console.
Nintendo's real exciting thing here though is not that their handheld might be much more powerful than Wii U, but that all future titles will likely be made for both devices, allowing the company to focus on releasing their 25+ titles across both and focusing not on making 2 versions of the same game (smash 3DS and smash U or MK7 and MK8) but on creating just one of those games in each series + new games in new genres while never having to worry about droughts, also Vita's love for indies should transfer over to Nintendo's next handheld, the barrier for 3DS is the old tech, but Wii U has strong indie support now and we could see this happen in both devices as releasing content on one could be impossible, meaning creating a title on a Nintendo platform means making a game for 2 devices at the same time with only fidelity changing between handheld and console.
The numbers have been thrown around by a GAF member, and he has shown that it is much more profitable to make 1 game for 2 devices than 2 games for 2 different devices, even if only 1 device gets the sales in this "NintendOS" setup. Another benefit is marketing 1 platform, "NintendOS" is easier than marketing 2 separate platforms, it becomes a much more compelling set up for Nintendo and makes too much sense.
We talk about how successful PS4 is with it's 18.5m units sold in 1 year and how brutally poor 3DS and Wii U have done across their 3 and 2 years respectfully, but together those platforms have sold ~60m units in 3 and 2 years combined, even if you threw out Wii U's market completely, ~50m+ units in 3 years is a market that Nintendo can release huge titles like zelda and xenoblade x and take risks because those titles have a base that can support them. 3rd parties while not being universally accepting of Nintendo, are much more likely to come back if they can make 1 game to target both a handheld and console together with a userbase of 50m+. Both of those platforms had horrible launch and first years, so that number might change drastically for the better, how many people here would buy/already own a device that came out in 2011 and played all future 3DS and Wii U titles? Bayonetta on a handheld? yes please!? How about Fire Emblem Awakening or Pokemon X/Y on a console? UH take my money.
This poor output Nintendo is stuck with supporting 2 platforms will be gone forever, that is what the promise of NintendOS is, so don't worry about the specs too much, even if the handheld is only 128GFLOPs, at 540p that is going to be very similar to Wii U and considering the ~4inch screen that they are likely to use? you'll be looking at a higher DPI than Vita, very close to smart phones from only a couple years ago in terms of resolution, with performance around the top of the line today.
