I only have 1 copy of Mario Kart 7 so I can't try.

There's download play.

Just email Nintendo,and see what they say.

This sucks to hear. Only reassures me that I shouldn't get this game. Since TBD already suggested redownloading I'm guessing you already did that, because it could just have been some weird bug with the first download.

It's not limited to downloaded copies. My gf and I refused to NOT have a physical copy for 40 dollars, we got them, we played 2 levels and quit due to the immense lag that occurred multiple times in those two stages. I hate to say this...(I'm in physical pain as I type) but, Nintendo released a Mario game that wasn't perfectly executed. Oh, 2012...why have you messed us over again?

It's your fault, then. Blame the wireless interference for that. Try getting closer and see what happens.

Okay, so seriously, I'm not sure what's happening with you guys. I've played quite far into the game now, on co-op with a friend, and I have NOT experienced any sort of lag whatsoever. I have a download copy and he has a retail copy. We are playing with 3D all the way turned up, and I am playing as Mario, and it's saving onto my system (the downloaded version). It is seriously playing perfectly and looks absolutely gorgeous. Just thought I'd share.

Yeah, wireless interference when sitting RIGHT NEXT to her...is totally my fault TheDreamingHawk. My bad. I forgot that I controlled all electronic interference at INCREDIBLY short range.

BTW though, love your avatar.

Are you connected to the internet? Try disconnecting/going outside and you can try again. Maybe your 3DS is being a pest and wants to connect to the internet at the same time. That's what slows down MK7 sometimes for me in local play.

Yeah, I sit next to my gf too when playing and it lags A LOT. I don't know what is the problem, I also bought a new SD card today just to see if that was the problem (a Sandisk 4gb class 6) but nothing changed, same lag.

P.S. Just to clear things up, I played the game this morning outside in the garden, same lag. The wireless interferance has nothing to do with this, it's a game problem (at least the downloadable copy, no idea about retail).

I have a Sandisk Pro 8GB and multiplayer games work fine. Haven't tried NSMB2 yet.

Every multiplayer game I have (MK7, Heroes of Ruin) has minor issues, but not like this.

Multiplayer games always worked fine here too, maybe some minor problems like in Mario Kart 7 but overall they work great. I'm talking about THIS game.

i feel for you this is poorly tested by nitnendo imo

I played for a few hours while sitting a few metres away from the other person while in a pretty crowded room full of other 3DS's and DSi's, while also connected to the Internet and I found it to be pretty much fine.

OK. Tested it with a friend who also DL the game.

It DOES lag, but not even close to being bad. Just a quick stop off and on when there are a lot of objects. It's only annoying in the map screen, but it's still as fun as ever.

Maybe they should send out an update to fix this, but regardless it works fine if you give it a chance. If you want bad lag, play Blazeblu: CSII on local wireless. The lag is so terrible the game goes out of sync and crashes unless you do it slowly.

It didn't lag with me, Digital playing with Retail.

It's a common problem with wireless interference. It's happened to me on Tetris DS playing at a convention and Zelda Four Swords in a mall, and I was close to the people I was playing against, but it didn't matter. It's obviously not the game when it doesn't happen in every location, so don't blame the game.

Yeah there not that many signals were I am at compared to other places.

Any solutions?
I have terrible slowdowns in NSMB2 co-op mode, both 3DS's use downloaded game from eShop.
I turned off everything wireless in the house, still the same.