Greenest MSXing!

MSXs alone consume less than 40 watts in general and OCMs much less.

That's really a low power usage for the FS-A1GT. A Philips VG 8020 is pretty simple and is on 24W!

Power wise:

FPGA <<< Raspberry Pi <<< MSX w/ some Chips integrated into one packaging chip < MSX w/ all discrete components

If we take into account that 5W is more than enough to reliably run a Cyclone IV with a MSX2+ at turbo speeds w/ disk storage, large mapper, SCC, OPL3, Wi-Fi and FM (it probably uses even less than 5W) and compare with a system similarly loaded, that power bill difference is even higher... Just a floppy interface or a Beer IDE with an IDE drive or a Mega SCI plus a SCSI drive will added quite a lot to the power bill, SCC and FM and mappers might add an extra 5 to 15 Watts depending on their design. Even a modern solution like SD Mapper or other All In One interfaces like Carnivore and GR8Net will add a couple watts over (and let's be honest that if we are comparing original vs modern, those interfaces shouldn't be considered as they were not possible at the time of "Original").

I don't think that a Raspberry PI emulating a MSX will be lower power than a Cyclone IV, as it has to run a guest OS and has a pletora of subsystems on the SOC that might be working on low power state or not, those use 12.5W power supplies and tend to run into issues with lower specced power supplies, and emulating, even though an older system at lot lower speeds, usually requires the CPU usage to be a little bit high and not allowing lots of power savings during emulation (I just remember of that whenever I run BlueMSX or OpenMSX and the fan on my laptop kicks in making lots of noise that it doesn't do while browsing the web or using office applications or an IDE for programming). But it will probably look favorable to a real system, even the ones that have chip integrateds, even more so if you count for additional hardware like mappers/scc/fm/etc

I need to find were I've stored my Kill-A-Watt and could easily supply the numbers for SM-X (FPGA, Cyclone IV), Multicore 2+ (FPGA, Cyclone IV, might use lower power as it doesn't have the MSX external bus and don't use +/- 12V on the power supply) and a Raspberry PI 3B+... Let's hope it is not at my mother house, if so, it will take quite a while until I go there again, but theoretically, I would expect FPGA to be less than 5W, Raspberry PI to be within 5 to 7W, a goood real system with integrated ICs and newer batches of other ICs to be around 10W and a the very first ones to draw 20 to 40W (I think the ones that would consume most energy would be the ones that were originally a MSX1 and then received conversion kits that added subslots, subbios, mapper, RTC and VDP on top of the existing boards, here in Brazil those kits usually required changes to the original computer power supply to make it give you a few extra Watts).