I have the stalling problem too. It's not the clock freezing. If I have more than one sim, one of them will stall, and the other one keeps going. All the while the clock keeps going and needs keep dropping. I'm not sure if the needs are dropping faster than usual but it could be. The first time I noticed the problem was when it took over an hour to go from the backyard to the toilet. Then it was taking 4 or 5 hours just to get leftovers from the fridge and eat them.
I give a command say, "Eat Leftovers..." and they stand around for a half hour to 45 minutes. Then they will start moving. If there is a door or archway in the way, more than likely they will freeze up just before passing through. Then they get to the fridge and stand there for a half hour. Then they get the plate from the fridge and stand there for a half hour. Then walk to the table, and freeze. Put the plate on the table and freeze. Sit down, freeze. Start eating, freeze halfway through. That's when I gave up, canceled and hit "Make All Happy" on the cheats.
After I patched, and then installed Into the Future, I had a problem with my saved games and had to make a new The Sims 3 directory and install all my store content again. I don't have any CC, and no mods at the time. I was able to copy back my actual game save for Lucky Palms and use that with 2 sims (Susan and Mary Test) that had just graduated from University. They went to the future and stayed there for 4 or 5 weeks before coming back to the present with their Plumbot. After they had been in the present for 2 more weeks, they started the stalling. I hadn't been using cheats before, but I had to keep using "Make All Happy" to keep them from dying. I installed the updated versions of Nrass Error Trap and Overwatch, but that didn't help, so I erased my mods directory to remove them. They had only been on one trip to the Future, and one return to the past before the problems started.
So I started a new game in Moonlight Falls with a single sim, still with no mods or CC at all. She went to the future, made some Plumbots, got married, engineered and engineered a child. It's been 4 1/2 weeks, they have made several trips back and forth between the future and past. No major lag yet, but it was 5 or 6 weeks on the other one before it got bad enough to noticed.