You're right though about the price.
Here's the numbers:
The GTX 260 is $329. The 4850 is $199.
The GTX has 896mb of ram. The 4850 has 512mb.
The GTX costs 1.65x as much.
The GTX gives you 1.75x as much ram.
And in 3D Mark and Crysis, the GTX is 1.25x as fast.
So, spend a 65% more and you get 75% higher res textures, and 25% more FPS.
Those aren't the only factors to consider of course.
Noise level:
http://www.tomshardware.com/reviews/radeon-hd-4870,1964-16.html
The 4850 wins here. But I have a GTX 260, and it seems fairly quiet to me, so even though it's louder than the 4850, it's not really loud.
Here's the numbers:
The GTX 260 is $329. The 4850 is $199.
The GTX has 896mb of ram. The 4850 has 512mb.
The GTX costs 1.65x as much.
The GTX gives you 1.75x as much ram.
And in 3D Mark and Crysis, the GTX is 1.25x as fast.
So, spend a 65% more and you get 75% higher res textures, and 25% more FPS.
Those aren't the only factors to consider of course.
Noise level:
http://www.tomshardware.com/reviews/radeon-hd-4870,1964-16.html
The 4850 wins here. But I have a GTX 260, and it seems fairly quiet to me, so even though it's louder than the 4850, it's not really loud.