Guys, read all the posts in the thread. Even GordonBGood, a long time Pentax user and poster on DPR, says the test is invalid. K-5 uses RAW NR (noise reduction) that like K-7, K-x, and K-r kicks in automatically at ISO 3200 and up and can't be turned off. So this test is comparing one camera with NR vs other with NR off.
http://forums.dpreview.com/forums/read.asp?forum=1036&message=36792981
"I would also agree but: The Nikon D7000 very likely doesn't use the "extra" high ISO raw Noise Reduction (NR) that the K-5 definitely does starting at ISO 3200, which has a strength to reduce the magnitude of the noise peaks by about a factor of two, so if one applied the same type of NR to the D7000 images then they would look about the same.
Getting real here, I don't think one chooses a camera from one of the D7000 or the K-5 for reasons of image quality or high ISO performance but rather for other features of each."
http://forums.dpreview.com/forums/read.asp?forum=1036&message=36792981
"I would also agree but: The Nikon D7000 very likely doesn't use the "extra" high ISO raw Noise Reduction (NR) that the K-5 definitely does starting at ISO 3200, which has a strength to reduce the magnitude of the noise peaks by about a factor of two, so if one applied the same type of NR to the D7000 images then they would look about the same.
Getting real here, I don't think one chooses a camera from one of the D7000 or the K-5 for reasons of image quality or high ISO performance but rather for other features of each."