Pentax K10D @ISO3200
There is that comparison of high ISOs between Nikon D700 and Sony A900. Here is my word on the same thing, but instead of a full frame CMOS from a cropped CCD. Go figure.
No noise reduction was used here. Note ISO3200 is not natively supported by this camera.
100% crop 1:
100% crop 2:
Looks bad? Um, no. Would I use 3200 in the wild? No.
The point is - what good is a high ISO comparison when there's more than enough light for a low ISO?