Panasonic G3 low-res images on playback - any hints?

I'm getting used to my new G3, despite the confusing menu setup - after years of using Canon 20D and 50D, various Canon and Sony compacts. The manual is not a big help, so I'm gradually finding answers to my questions online - but I can't find anything on this: I'm having a problem with the resolution of images on playback, both on LCD and EVF, when zoomed in. I noticed that zooming in on images to 16x in playback mode, they look low-res and blurry, like a JPEG that's been upsized in Photoshop - but of course the file is fine when I check it in Photoshop. I shoot RAW only, but on a hunch I switched quality to RAW + JPEG and the playback image is much better. So, is shooting RAW + JPEG the only way to get a decent, detailed image review, or am I missing a menu setting somewhere? I like to be able to check for focus or image shake on playback, and I can't with the quality I'm getting in RAW mode - it's bad enough that everything looks blurry. Any ideas? Thanks!