QUOTE said:
That is all opinions and personal experience with the different companies.
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Catalyst is the name of their drivers. Simply put, their drivers are terrible. While they continue to improve, NVIDIA drivers simply work.
Okay, I'll just assume you know more than I do (whether or not that's true) and return to a professional reviewer's opinion... oh wait, that's what I did - use a professional reviewer's opinion. CustomPC Magazine issue 094, arrived this morning with a fresh coverage over their recent Sandy Bridge motherboard labs test.
They say the MSI motherboard is the best value in the test (aside from the Maximus IV Extreme which they used only to overclock i7-2600K to 5.3Ghz out of the theoretical 5.7Ghz maximum). They go into detail on how the VRMs are the main feature of the board, which is able to keep cool even under heavy overvolting. Sure, the Intel Z68 motherboard and early releases from other retailers feature a whole bunch of extra features (like "virtual GPU" technology), but they're new and I'll wait for their labs test next month before saying Z68 is better than P68.
The disadvantage of using 1x4GB of RAM over 2x2GB is the fact that dual-channel RAM requires 2 RAM sticks. I'd only advise getting 1x4GB of RAM when they intend to get another 1x4GB of RAM soon, if not straight away.
Catalyst is not as "terrible" as you say, or at least not as bad as they were 4 years ago. That doesn't make them good, and nVidia drivers are better, but in many cases you'll find that mid-ranged graphics aren't nearly as affected by driver issues as high-end graphics. True that 60% of games will have the "nVidia: The way it's meant to be played" logo on the startup, but that doesn't mean that AMD graphics are incapable of producing playable framerates in modern games (as you seem to imply). I'm still using a HD4870, and there are no games that give me trouble.
As I said, the HD6890 is better than the GTX 550. The GTX 460 (768MB) is faster than the HD6890. The GTX 560 costs much more than any of them. There is a clear scale to the order of graphics cards, and if you just ignore the AMD cards, you'll end up either paying too much or too little for the amount of power you want. EDIT: Naturally, these facts are based off real-life performance in a range of modern games. If needed, I could even cite the exact page in CPC Magazine (and, in a couple weeks, provide the link to the review on bit-tech.net).