I am shooting with Nikon D7000 and 18-105mm lens and RAW only not (RAW+JPEG). When I import my pics in Lightroom 4 and zoom it at 1:1 both in Library and develop modules I see a lot of noise, though when I export them out as jpeg without any retouching they look fine. I even tried changing the file handling settings for catalog preview quality as high and preview size as 2880 pixel but of no use. Is there anything we can do to avoid such previews? I don't mind if LR loads fine quality pics but takes more time.
EDIT BTW the maximum resolution of my monitor is 1366x768
Example from LR Zoomed at 1:1