That sounds insane! What resolution did you set the first blur?
I think there is so much potential with the single device resolution settings and barely anyone uses it.
Especially with blurs, expanders and layout generators, in almost every case of using those devices you don't actually need a 1 to 1 resolution for those devices, I highly recommend everyone to try and mess around with that setting.
While we are at it, it would be amazing if you could change resolution of devices based on the group they are in, that could speed things up by quite a bit for large projects