Raspberry Pi 4 8GB is released today.
To address all this memory 64-bit version of Home Assistant needs to be installed.
But 32-bit for RPi4 is still recommended.
Does anybody know if there are any problems with 64-bit version of Home Assistant?
I did found one thread that gpio ports are not working… is this still an issue?
Could some addons not support 64-bit?
I have a RPI4 4GB and maximum i had in past using memory was 1.2GB. SO a 2GB version was ok as well. Why you want a 8GB then? 
Home assistant is one of those services in your home that’s expected to be up and running 24/7.
That property can be useful for lots of random services around the house (e.g. attach a 10T drive and backup your stuff)
HassOS also happens to run docker, for add-ons, and there’s also the portainer add-on to make it easier to run generic docker stuff.
You don’t need the 64bit version of Raspberry Pi OS (AKA Raspian) to run the 8Gb version, so I’m not sure why you’d need 64bit home assistant. You may well need an updated version of HASSOS to recognise the increased memory, but that should be the most you need.
I buyed 2 weeks ago raspberry PI 4 with 4 GB (to bad otherwise i would bought the 8 GB) and i am running it with the 64 bit version, because i want to use the VSCODE plugin. Until today there was not a technical reason to use the 64 bits version, because the 32 bits version could also allocate the total 4GB memory. With a 8 GB memory you have to use the 64 bits version, if you want to allocate all the memory!
The only problems i had with the 64 bits version, was with the modipy hasssion plugin from Bestlibre. He didn’t provide a AARCH64 base image to build the docker container. I used it for TTS message trough my connected USB speaker. Therefore i build my own mpd player addon, to solve this problem.
The most important addon’s i had where also available in 64 bit.
This could be a boost to support for more compatible 64 bits addon’s, because developers will see the need to make there addon also available for 64 bit systems. Now that the PI also has boot from SSD in beta, the advantage for a intel NUC seems to be less important.
Think of it like Microsoft office.
Your pc might have 16gb of RAM, so your OS is 64bit, but office is (was till a few years ago,.now they have 32 and 64) 32bit, just means each office app can onlu use up to 4gb (well less due to overheads and real world stuff)
The advantage is also as @risk already mentioned, Hassio is running on docker, so you could use more containerized apps if they don’t consume to much processor capacity. I see also a big advantage for Machine Learning, were mosty more memory is used. In combination with a NCS2 or a Coral this could be a very nice home system 
Shortly after the announced the 4GB version, they announced the dreprecation of the 1GB, and then a price reduction on the 2GB
They are currently working on the USB boot (full production rather than the Beta) so it just might be smart to wait a bit.
Assume we need to wait until we can run HA on this?
You don’t need to use the 64bit to make use of the 8GB memory. If you read the blog article it says;
Our default operating system image uses a 32-bit LPAE kernel and a 32-bit userland. This allows multiple processes to share all 8GB of memory, subject to the restriction that no single process can use more than 3GB
In most cases you won’t see the impact of the 3GB limit as the limitation is per process not per application.
Here’s a data point: I’m unable to get the 32 bit version of Home Assistant working on the new Pi 4 with 8 gb RAM.
Today i’m running a Rpi3+ with an SSD and it works great.
When i migrated from SD-card to SSD i installed Influx and Grafana.
But after 2-3 months running Influx container it would not start anymore, i looked at the debug log and found:
runtime: out of memory: cannot allocate 40960-byte block (551747584 in use)
fatal error: out of memory
That’s why i want to upgrade my RPI3 to a RPI4… maybe 4GB is enough for influx but when they released the 8GB model i thought i could buy this model instead if Home Assistant can use all the 8GB of memory?
My Pi 4 8Gb arrived last friday, installed Ubuntu 20.4 64bit/HA Supervised. With Influxdb and grafana installed, I now use 1022M/7.63G
Reading this and the running out of memory error, this is the reason virtual memory was created, one of the biggest flaws of the rasp pi range is the continued use of SD boot medium.
I have read many people of using this make and that make of SD card and battery backup, careful shutdowns etc. Fact if you have a SSD or regular hard drive for boot you have a 1 in 1000 chance of corruption, but is no longer any more compact or cheaper than cheap x86 platform. The software on the Pi is written to minimize SD card wear and in doing so shoots itself in the foot. With the Pi4 we now have a very capable processor, with a very incapable storage solution. If you want reliability and room for increased loads, dont waste your money until the original flaw is fixed.
My current uptime of my cheap X86 32 bit on my working system stands at just over 1.5 years…
… Just my 10 cents
I do run my Pi4 (and my Pi2 and Pi1) from 2,5 HDD.
I sold my old first gen i5 8gb ram laptop for 50 quid.
Battery even still lasted an hour !
I have also run my pi3 b+ on a2.5 hdd with no problems at all, I even played around with the swap file settings to make more memory avail to apps. Apart from the fun of getting it all to work properly, I always felt that the solution when finished was no more compact than mini PC, and the X86 single core atom processor still ran circles round the quad core Pi, when it came to performance. In short interesting, but not worth the effort