when the RAW file is put into Photoshop it appears that some sort of noise reduction has been applied
You must mean you open the RAW file in camera RAW or something. You cannot open and edit RAW files in photoshop itself as explained by this :
There's no question that Photoshop has become the world's most popular and powerful image editor,
but one thing Photoshop can't do on its own is process raw files. If you remember from a
previous tutorial, raw files contain nothing more than the raw image data captured by your camera's sensor, with no processing of any kind (which is where the name
raw comes from). To work with these files, we need to use special software that knows what to do with the raw data. Adobe came up with two great solutions. One is a completely separate, standalone application known as
Adobe Lightroom. The other is a free plug-in for Photoshop itself -
Adobe Camera Raw - that ships and installs with Photoshop. Lightroom is a standalone application (it needs to be purchased separately) that includes additional features to help with your overall workflow, like the ability to catalog your photos. Camera Raw is strictly an image editing application. However, both Lightroom and Camera Raw use the exact same image processing engine, which means both are equally capable of giving you fantastic results.