I have been running ha on a 10 year old laptop which is starting to give up the ghost. So I am looking to move to a Raspberry pi instead.
Will I see any noticeable difference using a 4 or will a 3b be ok?
It will be running HA, node-red and mosquito.
I have been running it in docker containers. And would quite like to stick to that rather than hass.io mainly because it’s what I know.
Many thanks in advance.
No one ever got sacked for buying too much RAM, so get a Pi4 with maximum RAM.
Run from a SSD (/boot will need to be on SD card at present).
The 4 is much faster and will be noticeable, the other bonus is that it has USB3 so you can run a SSD off it so your not limited to SD card speeds (which is even more noticeable!). Even if that is not your plan now you’ll have the option later unlike with the 3. Personally I would get the 4Gb version, it’s not strictly needed but what’s not used by your programs will be used as cache.
Note that the 4 runs hotter, you do need heat sink and maybe a fan spending where you install it.
AMD Ryzen 3 or 5. When you add many ip camera in ha rpi will slow down. You cant normal use “preload stream”, because after 10 min work rpi freezes.
I have a Pi 3 and Pi 4, and the 4 is noticeably faster especially when running from SSD.
Not to hijack the thread, but personally, I considered the Pi4 as an upgrade to my old Pi3+ - and then figured that if I was running my entire home automation platform on a single device, and I didn’t want said device to possibly die b/c of a known issue of frying an SD card - that I’d just step up to a NUC. Did so a few months back and haven’t looked back. Grabbed one for ~$200 on eBay and have been really pleased w/ the results.
If you are looking for more power and more robustness than a RPI, then another option is to looks at running HA from Docker on a NAS such as a QNAP or Synology. I personally run HA on my QNAP and am very happy with the solution.
So now you have a single point of failure NUC? 
I’ll take a NUC any day of the week over what is certain to be eventual SD card failureS on a Pi…
Oh, it’s no doubt more stable than a raspi ( 3 or 4 ), but still you’re one hard drive failure away from being very sad and upset
TL;DR: Backup today! (and tomorrow … and every day)
That goes without saying!
thanks all, after all the coments i have replaced fans etc on the laptop and added external cooling which is why i was moving away from the laptop.
i will set up an old laptop as a backup
Are you using Z-wave devices? The one thing that’s kept me from even considering a NAS for HASS has been that there didn’t seem to be an obvious way to get one to talk to a USB z-wave dongle.
I’ve moved my Home Assistant, formerly known as HASSiO, over to RPi4 as my 3 was very sluggish.
Tadaaaa! Way faster and more responsive, whish I’d done it ages ago. 
i’m also considering switching to a Rpi 4.
Has anyone compared the bluetooth range of a Rpi 3B+ vs the Rpi 4 ? I have quite a lot of Xiaomi bluetooth temperature sensors and I wouldn’t like to lose connection with some of them.
Make sure to replace the sqlite database with e.g. MariaDB
Your Lovelace will load so much faster still.
If you are going to be doing a lot of processor intensive things like motion detection on cams with ffmpeg I would go with the Pi4 with 4gb, other wise the pi3 will likely be fine, Just do your backups whenever you make a change to your config and store them off of the SD card.
I will be moving to a Pi4 4G model soon. I’m running on a Pi 3B+ now with an SD card. Regarding the SD card, just treat it like any other kind of maintenance. We change our oil, change our filters on our HVAC units, etc. I change my SD card once a year and keep the old one as a backup. I run the Hass.io Google Drive Backup daily with my own API key with 2 months, 2 weeks, and 3 days historical (7 total retained backups). It’s all automatic. I feel very comfortable that I am protected against failures. And good 32 GB SD cards are about $10, so we’re talking very minimal yearly maintenance costs.
When I migrated from a Pi3B+ & SD card to a Pi4 4Gb with USB3 SSD, I had always been using the bluetooth device tracker for my phone. But after installing the Pi4 I found the bluetooth range extremely limited, like no more than around 2-3 metres. Further investigation revealed its a known issue with USB3 interfering with 2.4Gb bluetooth signals.
In addition to the device tracking issue I had bought some of the Xiaomi bluetooth sensors and quickly realised I needed a different setup so I now run Esphome on an ESP32 module. Its great and covers the whole house for the sensors. For the device tracking though I changed to using the router with IP tracking.
I use a raspberry pi but not as you’d expect. My server is in a corner of my house and I needed my usb dongles for zwave and zigbee to be in the centre of the house. So setup a raspberry pi with rasbian, plugged my usb dongles into that then shared them across the network using usbip back to my server. Has worked 100%, very happy.