Are there documented rendering differences between different versions of an operating system and same versions of browsers?

I'm involved in some browser-compatibility test开发者_JAVA技巧ing, and we're looking at tools and so forth. One thing we need to do is visual inspection of our site in a range of different browsers on different OSs and platforms.

My question is whether there are documented differences (or someone can post some HTML+CSS) where a page will render differently in IE6 on Windows 2000 than it will in IE6 on Windows XP (say). Or IE7/XP vs IE7/Vista. Or Safari4/MacOSX Leopard vs Safari4/MacOSX Snow Leopard.

We're hoping to be able to slim down the count of combinations.

I've seen this other SO question, and don't think it's quite the same thing. The answers direct me to quirksmode.org. We're not looking for a breakdown of which elements/CSS-rules are supported in which browsers; we've got an existing site that for better or worse uses what it uses, and we'd like to get it under test to be able to make changes more safely.

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You can submit to http://browsershots.org/ multiple times, eventually a different OS version will get called for the same browser version. This is not the ideal solution.