toomanycanons: My D5100 stayed with the big boys up to ISO 3200.
You must be delusional or by "big boys" you aren't referring to the D4. Side by side, the D5100 is noticeably worse than the D4 even at ISO 200. Some colors (magenta, purple) are horrid even at 100 on the D5100. If you're by chance looking at jpeg instead of raw, you might also want to note the loss of detail in the D5100's NR.