Can PJRC top this board someday?
That really depends on how you compare. PJRC definitely will not make a $99 board. So you should not expect to see any Teensy loaded with as many chips as this Portenta H7, especially the SDRAM and Murata Wifi. I'm also pretty skeptical about those 2 high density connectors, but will be watching closely how people use them to influence decisions about future Teensy boards.
In terms of raw performance, an
1170-based Teensy (M7 at 1 GHz and M4 at 400 MHz) ought to be about double Portenta's speed (M7 at 480 MHz and M4 at 240 MHz). NXP's 1170 doesn't exist yet, but we can generally expect it'll arrive near the end of this year. Presumably more STM32 chips will arrive over time.
Then again, if you only care about raw speed, how does a 600 MHz M7 without companion M4 compare to a 480 MHz M7 plus 240 MHz M4? I don't believe there as any single simple answer...
Of course these STM32 and IMXRT chips are not the end of Moore's Law on microcontrollers. We're just now seeing the beginning of chips at 40nm and soon 28nm. ARM has already announced
Helium using architecture version 8 and vector processing optimized for machine learning and DSP, and competitive pressure from RISC-V is likely accelerate the traditionally slow pace of improvement on chips aimed below phones & PCs.
The reality of all this advanced hardware is a strong dependency on software support. Many people will just compare hardware specs or coremark scores and ignore the quality of driver support. But drivers & libraries matter quite a lot. I believe everyone who uses this forum regularly has seen the huge changes in USB speed since the early days of Teensy 4's beta to where we're at now with 1.49-beta4. Even at 12 Mbit, software matters greatly. If you run the
lines/sec benchmark on various boards, you'll see huge differences. Even Teensy 2.0 competes with some of the non-Teensy 32 bit boards that have not well optimized code.
These new chips are bringing so much complex hardware that will need a tremendous amount of work on the software side. When you see a company like Seeed Studios make a board, you can be pretty sure the software support will be only whatever the semiconductor vendor or some 3rd party like Zerynth provides. Arduino has the potential to really craft some amazing software support. But it could also turn out like Arduino Due. At this early stage, I don't think anyone can predict where it will end up.