At that resolution, if you're hoping to see us see a difference in AA resolution based on a pixel size, we won't. Lol Could probably even go lower AA wise. Image is just too small vs pixel threshold size.
You also save as a jpeg which will change all the noise/construction of the image. Should be a PNG.
Take a look at a difference. Cause of compression, whole image is different on a pixel level. Cause jpeg is going to change all the data on a per-pixel level with compression, and it's not uniform one go to another, so side by side will yield different results on each half. Biggest change seems to be boundaries of shadowed areas.
We need to see a much larger image where the pixel noise threshold can be seen at a pixel level.
But to sum up, at that size, even with different AA, the difference couldn't really be seen so small I think, plus with how AA works, I think the construction of pixels will be random each time as it decides paths to take on a per-pixel basis. Think like noise, almost.