Originally posted by the ninjak
Never seen him perform a significant strength feat.
And you won't find any that compare to the big dogs like Thor and co. He's kinda like Norrin in that he doesn't have many quantifiable strength feats. I can only recall in his weakest incarnation he was able to lift an apartment building. He has lifted a huge submarine out from underneath the ocean but had some help.

Currently -this being his most powerful incarnation- Marvel has him listed as a 7 (incalculable) in strength with the ability to increase as needed. This is in all of the current handbooks, including the bio in his annual. I've reviewed all the info and it was an excellent, well written bio.

http://i1215.photobucket.com/albums/cc513/dmills31/1311460425721.jpg

As far as current on panel stuff goes again there's not much in the way of lifting feats, but we do have some pretty solid anecdotal evidence that gives a clue about his strength level.

Venom for example has been able to physically give both Colossus and Namor a tough time. Nova dispatched him with a fairly casual backhand.

http://i1215.photobucket.com/albums/cc513/dmills31/1311456669512.jpg
http://i1215.photobucket.com/albums/cc513/dmills31/1311456685772.jpg

Klr't, who is roughly Thing level, wanted no parts of engaging an attack ship that Nova was able to oneshot with a grav punch.

http://i1215.photobucket.com/albums/cc513/dmills31/1311456780486.jpg
http://i1215.photobucket.com/albums/cc513/dmills31/1311456791593.jpg
http://i1215.photobucket.com/albums/cc513/dmills31/1311456853154.jpg

He was able to halt a bloodlusted mature Technarch (planet buster) in mid charge. This just after recovering from the transmode virus.

http://i1215.photobucket.com/albums/cc513/dmills31/1311458695065.jpg
http://i1215.photobucket.com/albums/cc513/dmills31/1311458705238.jpg
http://i1215.photobucket.com/albums/cc513/dmills31/1311458716980.jpg
http://i1215.photobucket.com/albums/cc513/dmills31/1311458730779.jpg

Korg punches Nova to no effect at all.

http://i1215.photobucket.com/albums/cc513/dmills31/2011-06-05130001.jpg

^^^This one some may consider flimsy, but its still a useful indicator imo. Usually in a direct physical encounter, if one strong dude punches another to no effect whatsoever, then that's usually a comic device indicating that one guy is significantly stronger then the other.

There's more I can post, but this should be enough to give us a rough estimate of where he is physically. My take has been that he's somewhat above bricks like Colossus, Korg, Namor, et al, but still below the big guns like Thor, Supes, Hulk etc.