FastRawViewer is described as 'extremely fast RAW image viewer that allows the user to see the real RAW-data and the real RAW histogram, and it supports virtually every camera format' and is an app in the Photos & Graphics category. There are more than 10 alternatives to FastRawViewer for a variety of platforms, including Windows, Linux, Mac, PortableApps.com and Electron / Atom Shell. The best alternative is FastStone Image Viewer. It's not free, so if you're looking for a free alternative, you could try JPEGView or gThumb. Other great apps like FastRawViewer are qimgv (Free, Open Source), FastStone MaxView (Paid), Universal Viewer (Freemium) and FastPictureViewer (Freemium).