Good question; so the thing about Steam Deck is it's using RDNA 2, which we know doesn't have hardware-accelerated logic like Tensor Cores for ML tasks. If a Switch 2 would be using some Nvidia GPU variant with Tensor Cores in them, they could probably skimp on targeting TF performance exactly in line with Steam Deck, but have comparable performance anyway, as any tasks with image upscaling or ML that on RDNA2 have to be spread to the CUs, could be done by Tensor Cores on a Switch 2. Not that it'd have too many of those cores, but enough for Nintendo's budget.
It doesn't really need the I/O throughput of the PS5 or even Series systems tbh; the idea of a decompression block being there would be so Nintendo could stick to economical forms of media and storage delivery while boosting bandwidth with decompression. You've read some of my other hardware speculation stuff on GAF; there I've been a proponent of 10th-gen Sony & MS systems ditching discs and using cheap, "decent-speed" microSD cards for physical media of retail games. By the time 10th-gen systems are ready, 80 MB/s or so microSD cards at 32 GB or even 64 GB capacities should be doable for like a dollar or less at mass volume, so that's not much in terms of packaging BOM costs for retail games. Then with decompression you can boost those speeds to over 250 MB/s easily.
If Nintendo wants to keep things economical but still not be left behind tech-wise, IMO they're gonna need some decompression I/O block. It'd allow them to stick with slower internal storage, even under 1 GB/s, but have good enough decompression rate for their hardware even with lossless compression. Their decompression I/O wouldn't need to be as robust as Sony's or Microsoft's in terms of the ratio, but they need something.
GPU-wise I think it's more important they have a good mix of general compute, fixed compute (ROPs, TMUs etc.), hardware-ASIC compute (Tensor Cores) and hardware ASIC decompression I/O. Feature-wise they need to at least be somewhere in the ballpark of what Sony and MS are offering, mainly to ensure they can get as much 3P support as possible . If they have all the same features, then it just becomes a matter of scaling things appropriately for Nintendo's hardware. OTOH if they skip on something like decompression I/O subsystem altogether, that's now Nintendo requiring 3Ps to write two different file I/O systems; one for PS5/Xbox Series/PC, and the other for Switch 2. It could upset 3P partners and also hamper their own teams internally WRT game design features in future 1P games.
