When I had my 1048, it was tucked up under the floppy cage. I mounted it with screws and nuts through oversized holes that contained rubber grommets for vibration isolation, not that it needed much isolation. With the through-case airflow I had, it was about the same as my skin temperature.
I upgraded to the 1250 and things definitely changed. Since I could not fit it in the same place, I sat it in the bottom of my case. It vibrated quite a lot more and the vibration propagated through my entire case until I set it on some silicone rubber padding. I did not retain it with screws because it was heavy enough to be relatively immobile and any time I ran a screw through it to the case, the vibration once again had a propagation path to the case, though to a lesser degree. It gives off a lot more heat compared to the 1048 and I had to increase the throughcase airflow to get its heat out of my case or else the temperature would slowly go up. It was not a big deal, but definitely something to plan for on a yet to be built system. If you put a ferrous based tool near it, you can feel the magnetic field it gives off quite distinctly compared to very little from the 1048. Those observations are the price you pay for the increase in flow rate and head tolerance. With my particular setup, going from the 1048 to the 1250 netted me a whopping 1C improvement in CPU temperature, but then my system is designed to pose a low flow resistance. I can imagine that with the current popular impingement blocks (higher flow resistance) the jump from the 1048 to the 1250 would have a greater positive impact upon performance.
Hoot