5d iso grid pattern (banding?)

Hey I'm new to Canon. I had a Pentax kx, then switched to the Canon 5d classic. I am concerned about the patterns I get with high ISO. There is a bit of a grid pattern going on in many of the photos (is it called banding?). IN the example I have pushed it post processing a little bit to make it more obvious. While I don't mind noise, especially if converted to black and white, I do mind this woven looking pattern going on. Do you know if this might be because the camera is old, or is this something that is going on with other Canon cameras as well? If I upgrade to 5dII or III am I going to have the same issue? Do i need my camera fixed? Is there any way to fix this pattern PP?

what raw editor are you using ?

Welcome to Canon.. that is a very known behavior with canon sensors they don't tolerate much shadow lifting because you will see that, even on newer cameras happen that, search for canon banding.

Sure you can "reduce" that, if you use Canon Digital Photo Professiona (DPP) Software..