i run i2p on rpi 3’s, you can modify some things so it uses less resources. the 3’s won’t handle being a floodfill very well from what i’ve found so make sure you have that off. also i’ve only ever tested this headless, not sure if using gui or not. overall unless you want to do a lot of file transfers or really want to use the included features in the java router id recommend sticking to i2pd with the rpis.

biggest thing is i2pd uses way less resources. really shines for low power devices and for running long-term as a transit node. i notice pages load faster and had less issues with irc. the default tunnels is 5000 so i’d change it to maybe 3000 in config file if you’re pushing a lot of traffic through it. even so it never seems to fully utilize the cpu.

java uses much more memory and hammers the cpu. i’ve found for whatever reason i can achieve more overall throughput though, so i run java on a couple 3’s. You can also set the max memory for the java router to lower. Seems to me that overall number of tunnels consume more memory (much more in java) and throughput is limited by cpu. you can reduce the number of participating tunnels if it gets unstable. I also overclock the cpu a bit to around 1300.

also i wouldn’t personally give access to the router directly if you care about maintaining anonymity. you can access it safely with vpn/ssh. you could probably do some sort of in-proxy if you want other people to be able to use i2p without needing a router, i’ve never done this myself though.