I'd echo the other posters.
FastPictureViewer Pro is great for culling images, as it can be real time saver if you take tons of photos and need to quickly narrow down your "keepers". I was working on a camera review with a tight deadline a while back and made use of it, since I had a PC failure and did not have time to reinstall my usual Operating Systems and Software, and needed to make use of a new "emergency replacement" PC with Win 7 on it, making as few modifications as possible at the time.
I was very impressed with it's speed at the time. I did see a few bugs at that time trying to use it's batch features to move images rated higher to separate folders as keepers. But, Axel (the developer) patched them *immediately* upon me reporting the issues.
That was a while back, and from the looks of it now, a *lot* of new features have been added to it since then. So, I'd definitely give it a test drive to see how well it works for you.
However, as fast as it is, at it's current price, I'd also try something like Corel AfterShot Pro (which is also very fast but has loads of image management/editing features included, too). Like FastPictureViewer Pro, Corel AfterShot Pro can also use GPU Acceleration to speed up processing and rendering of images (only it uses OpenCL for that purpose, and I think FastPictureViewer is using DirectX functions). In any event, I think you'll find both are very fast. So, I'd test drive both products to see what works better for you.
FastStone Image Viewer is also a good program (and it meets your "free" requirement). I've spent time using in the past (although I didn't use it specifically for culling purposes).
Again, my personal choice for that kind of thing is Corel AfterShot Pro.
It's very similar to Adobe Lightroom, only faster on multi-core CPUs from my experience with it, and it allows you to very quickly rate images for culling purposes. It has lots of ways to accomplish that (including simple flags for keepers, as well as using a "star" rating system (one star, two stars, etc.) so you can quickly filter your views to show only the images you rated x stars or higher, then rate them again until you get the images you want in your final set.
I use it when I may take a thousand or more images in a weekend and need to narrow down my choices to a a couple of dozen images quickly. Basically, I just rate any "prospect" as 3 stars or more and filter my view to only show those images. Then, go through them quickly and rate the the better ones as 4 stars or higher, etc. It lets you zoom into parts of the image using a magnifying glass to quickly compare details of side by side images of the same subject, etc.
It's also got tons of editing capabilities, image management features, and even supports features like layers and edit regions. It's super software at a great price, and it's multi-platform (Windows, Linux, OS X).
It's not free, but it's the best software I've found for that kind of thing; and it's a real bargain at current prices.
They just started a new sale where they dropped the price to only $29.99 (the lowest price I've ever seen for it). So, I'd act fast if you want to get it at that price before they increase it again.
http://www.corel.com/corel/product/index.jsp?pid=prod4670071
Download a trial to see how it works with your camera's files first. If you like it, just buy it and you can just plug in the license key they give you with no reinstall needed.
I'd suggest watching this old "webinar" about it so you get a better idea of what it's capable of, since it's got so many features it can take you a while to discover all of them on your own.
It's really very nice software, it's *very* fast, and is perfect for what it sounds like you're looking for. IMO, it would pay for itself in time savings from one weekend's shoot compared to most any other similar solution (including products like Adobe Lightroom).
You can download trial versions of AfterShot Pro or FastPictureViewer Pro..
So, I'd take advantage of the trial downloads to find a product that meets you needs better.
Of course, FastStone Picture Viewer is free. So, make sure to test drive it, too.
But, a product like AfterShot Pro has gots loads of features you don't get with a free product like that (and again, it's current sale price of $29.99 is the lowest I've ever seen for it, but I don't know how long that sale price will last).
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JimC
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