I think on higher end cards you'd be just fine, but I think I can safely say my HD4670 just doesn't have the performance to enable decent FPS when running the games so far.
That was with the open source driver for my ATi card. I then installed the latest 64 bit Catalyst 10.11 driver, and it made an instant difference to performance.
That said, TF2 now refuses to run since changing from open source GPU drivers to the genuine drivers from ATi.
Right now its hard to say really, I need to do more work before I can come up with any reasonable answers - But i think with my planned HD6870 upgrade, even with the GPU only running at 50% it output in Linux, I'm going to see massive improvements, assuming the official drivers support it correctly.
What I have found out so far though:
1. Steam installs, updates and run without absolutely any fault of any kind.
2. I linked the "steamapps" directory from my W7 SSD, and it will happily use this meaning I don't have two seperate downloaded files to run it in each OS.
3. Portal, HF2 (all of them), all work - All be it slower than they should.
4. "shift/tab" works absolutely fine in games, and I was even talking to Matthew earlier whilst testing the features in linux. So it works fine in that respect.
5. Portal ran without any real noticeable difference, but the screen immediately proceeding the Valve picture was badly distorted - It however went to the main menu absolutely fine, and then proceeded to start up, and play fine - With the exception of it feeling like it was underpowered GPU wise and slightly glitchy as a result.
6. TF2 no longer works since changing from the open source driver to the AMD supplied Catalyst 10.11 driver. So I need to investigate that, and maybe try running it directly from its game folder instead of through steam to see if it makes a difference.
There is probably more, but I've forgotten, as I'm not really doing this as a full report style analysis. Once complete though, if the findings are good, I may consider a step by step guide to achieving it all.
The problem is, proprietory drivers in my experience have a nasty habit of breaking the desktop, and recovering the damage caused by there installation is somewhat tedious at times - Unlike Windows its never going to be a one type does all affair unfortunately. That said, it should be good for Ubuntu 10.10 based installs though.
If I can get it running properly to a point where its feasible to test it all, I'm quite happy to listen to advice on how to do it fairly, and correctly and then do said reports. I think its safe to say it will never be as good as Windows though, with the exception of GPU performance. If you have enough GPU capacity spare, then you should be able to run them at very good settings. Normally my HD4670 is good for most games (I'm yet to find one that won't play and that includes Crysis), but its no powerhouse either, and I feel I'm seriously pushing the boundaries with this card for games in Linux,
The impression I get is they just don't work with the same efficiency as they do with Windows. So while windows can use the full 100% of my GPU, I doubt Linux is using 60% of it when you factor in the way Wine is effectively translating everything into a way Linux can understand. With that in mind, I think its logical to assume that during this process of "translation" I'm losing GPU performance - If I had a HD6870 I dare say the loss would be less suficiant. Once I have my MomentusXT or SSD drive for linux installed, and my HD6870 we can really see how the performance is!
how do like mint? presumably it's independent of cannonical?
I quite like it actually. Ubuntu was the first distro I ever used, and despite wanting to advance further with distros like Gentoo or Slackware I've always kept it running on something - My MSI laptop uses Ubuntu 10.10 netbook edition to great effect.
Linux Mint can use either Debian as a backend, or Ubuntu - In pretty much all the regular GUI environments (I've forgotten the real name for this), but Gnome is my favourite. KDE, XFCE and others are offered though, as is 32 bit and 64 bit versions.
It comes more media friendly more than anything, so you don't need to mess around getting codecs and settings, flash and java in order to make it "everyday workable". I also like the menu, which is very KDE like, but without the really annoying way you navigate the KDE program menu - Something I can't stand!
All in all I'm very impressed, and prefer the cleaner, more Gnome "default" look of the GUI. In recent times Ubuntu/Canonical have gone the route of customising and almost creating a "Ubuntu Gnome GUI", rather than use the one produced like everyone else. I don't like things like the social networking menu in Ubuntu, which of course isn't in Linux Mint.
More crucially, because its Ubuntu inside, everything works as Ubuntu should, down to the software and methods used to install it. So its got me to somewhere I'm happier, without sacrificing the knowledge I've learned for Ubuntu over the last several years.