IME, SD 1.5 base model, IIRC (I don’t use the base model much) works tolerably well with the larger dimension at 512 and the smaller dimension between 384-512, and quite a lot of SD 1.5 based checkpoints work pretty well up to a larger dimension of 768 (some with smaller dimension up to that, too.)
But SD also has hard requirement that the output dimensions be divisible by 8 (I believe as a consequence of the pixel space to latent space ratio being 8:1 in each dimension) so its not surprising that 544x544 fails hard.
But SD also has hard requirement that the output dimensions be divisible by 8 (I believe as a consequence of the pixel space to latent space ratio being 8:1 in each dimension) so its not surprising that 544x544 fails hard.