To be fair... The games generally speak for themselves that... Even in portable mode it is punching above the Xbox 360 and Playstation 3.
I honestly haven't seen concrete evidence of this yet although it may well be true but I think when we see how the retail version of Skyrim performs in portable mode that will be enough evidence for me if it runs well. It may simply be that the frame drops of 360 and PS3 are replaced by a dynamic resolution on Switch but for me that still gives the Switch a huge advantage and the PS3 version of Skyrim had massive issues the longer you played 'rimlag' which for obvious reasons I'm not expecting to re-appear on Switch as that was due to limited memory.
When you look at the spec's there are many shortfalls in the Switch, low CPU performance, limited memory bandwidth, low GPU performance in portable mode and a restriction on storage capacity generally that makes heavy compression and compression artifacts likely in many games. The function of instantly toggling between portable and docked mode and vice versa also places restrictions on assets which have to be shared between both modes. However the huge improvement in memory capacity over 360 and PS3 should not be underplayed plus the decent Nvidia GPU architecture and its much improved feature set.
However I've seen too many games on many formats that look good running on development hardware but take a noticable nosedive for retail versions. Their so called final polish before release often just seems like an effort to optimise to get games to run as well on retail hardware as development hardware and it often fails. The thing with Skyrim in portable mode was the Switch's shown still had the cable coming out of the bottom which could have kept them running in docked performance mode. Looking at this video the cable was even secured with a screw to prevent removal. If nothing else showing the Switch in portable mode connected with a power cable means little regard for battery life and the retail version may be dialed back considerably to get decent battery life. So portable performance is my main concern.
GPU even in portable Switch mode is stronger and much more capable than PS3/Xbox 360 GPU, PS3/Xbox360 GPU has 230/240 GFLOPS, Switch in portable mode has 196.6 GFLOPS, but you here trying to compare buy raw numbers Nvidia GPU tech from 2005. and Nvidia GPU tech from 2015. and of course that Nvidia GPU tech/architecture from 2015. is stronger and far more capable despite raw numbers based from 2005. tech. not to mentione incrased GPU power in docked mode where Switch GPU is 393 GFLOPS whitout any gains from incomaprible newer tech and aricture. Somethinig similar goes for CPU, Xbox360 and espacily PS3 CPU were vey strong (and very complicated) for 2005. but Switch ARM A57 quad CPU is more capible and more subitible for modern games that have moder tech and arhitecture. Add to that 6-8x more RAM and its very obvious how much Switch is stronger and more capabile than Wii U, not to mentine PS3/Xbox360.
Buy you dont need specs, just look games, almost every multiplatform game that exist on PS3/Xbox360 on Switch is working at higher or more stable frame rate and higher resolution. Resolution on over 90% Switch games is 900-1080p, on PS3/Xbox360 we had only few games that had resolution above 720p and actualy we had plenty of game that had resolution belowe 720p and huge number of games had frame rate problems. Its already confirmed that Skyrim for Switch is based on Special Edition Skyrim, and we saw few time that FPS is rock solid in portable mode.
Also, Switch is new hardware, we still didn't see what Switch is really capable for, Nintendo and devs, yet need to start using most of Switch hardware.