Quality drop when converting RAW images to JPEG?

[PeteRob]

I did an experiment. Camera to raw+L, picture style standard, sRGB colour space. With DPP, colour space sRGB, convert RAW to JPG using "as shot settings" and quality 10. DPP conversion gives double file size (9587 vs 4785) a bit more contrast and a bit more saturation. I can't see any difference in sharpness.

[Kenby]

Could the problem be due to too high a setting for noise reduction? On my software if set too high the effect is like using the median noise filter in Photoshop with marked loss of detail.