Yes, memory is 1GiB by default, however the QEMU maxmem was 32GiB in my case, see /run/incus/<instance>/qemu.conf. But I found that 8GiB is not the limit even in my case actually, it is somewhere between a maxmem of 21000MiB-22000MiB. I assume that the phys-bits determine the amount of addressable memory, in the case of my CPU that seems to be less than 32GiB so QEMU complains about the maxmem of 32GiB for a good reason.
# incus profile show default
config:
raw.qemu.conf: |
[memory]
maxmem = "6144M"
security.secureboot: "false"
description: Default Incus profile
devices:
eth0:
name: eth0
network: incusbr0
type: nic
root:
path: /
pool: zfs
type: disk
name: default
used_by:
- ...
~ $ grep -m 1 'model name' /proc/cpuinfo
model name : Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
~ $ grep -m 1 'address sizes' /proc/cpuinfo
address sizes : 36 bits physical, 48 bits virtual