Sorry for not understanding your request earlier, but you are indeed correct. Something like prime95 without GPU stress seems to increase the liquid temp by about 5-6 degrees after 4-5 minutes. I also forgot to say, my GPU is terribly long, and so it barely touches the pumps (I mounted my AIO so that the pumps are on the lower end; Gamers nexus idea). Could that be the case?
No, my case can't handle that, unfortunately. It is front mounted with the fans as intake.