Pretty much all 3pts will lift a fair bit more than the loader. But you are talking 1-2' vs 8-10'+. Extra stuff & distance like a QH starts eating into lift capacity pretty quick. But you just have to look at tire & axle size to figure out which is the real business end of the machine. I dont wory about a heavy load on my 3pt. But I start worrying about my front axle even with proper ballast on back when things get heavy up front.
I wonder... It was certainly true with my other tractor. But you could see that from the specs (840 full lift loader at pins vs 1300 for the 3 pt 24" back). So there really was no comparison.
But the newer tractor has 3727 breakout at the pins (2,761 full lift) compared to 3,000 at the eyes and 2425 24" back on the 3pt. If the center of the log is 3 ft. past the pins the loader should be able to lift ~2600 off the ground. At 3 ft past the eyes the 3pt should lift 2,137.5 lbs. So I won't be surprised if the 3pt can't lift what the loader can lift. The loader is really strong for this size tractor.... Last week I lifted a log then got off the seat to do something and after I got off the seat I saw the log lowering it's way back to the ground. I thought my hydraulics were leaking at first, then I looked back and saw the back end slowing lifting into the air. And this was with 1,500 extra pounds on the rear of the tractor. So it's a strong loader for the size of the tractor.
But as you said, the rear is the business end of the tractor and that's where I want the weight. My loader may be able to lift a certain amount, but I really can't drive with that amount. too tippy. Plus I cringe at having those forces on the front axle when moving (dynamic load with bumps).
What I learned with my little tractor is that a 3pt can lift anything as long as the front will stay down. Even if you max the hydraulics, just lift the front of the tractor with the loader while lifting the 3pt; put the front back down and your 3pt is up. Or just run a come along from the top of the cage to the forks
Now I'm thinking what would be really cool back there is a rake style grapple. Back up to the logs, clamp, lift, go!