Try benching the X850XT PE, 6800 Ultra and the 7800 GTX at resolutions higher than 1600x1200 (i.e. 2048x1536) and you'll see where the 7800 GTX really shines.
1600x1200 & 2048x1536 Benchmarks:
Battlefield 2 1600x1200x32 (4xAA, 16xAF)
(Source:
Firingsquad)
------------------------------------------------
7800 GTX -
63.7 FPS
X850 XT PE - 33.8 FPS
6800 Ultra - 34.7 FPS
Battlefield 2 2048x1536x32 (4xAA, 16xAF)
(Source:
Firingsquad)
------------------------------------------------
7800 GTX -
38.6 FPS
X850 XT PE - 9.3 FPS
6800 Ultra - 13.4 FPS
Far Cry, Training Demo 1600x1200x32 (4xAA, 16xAF)
(Source:
Firingsquad)
------------------------------------------------
7800 GTX -
65.7 FPS
X850 XT PE - 54.4 FPS
6800 Ultra - 51.2 FPS
Far Cry, Training Demo 2048x1536x32 (4xAA, 16xAF)
(Source:
Firingsquad)
------------------------------------------------
7800 GTX -
45.6 FPS
X850 XT PE - 28.7 FPS
6800 Ultra - 25.2 FPS
Far Cry, tr3-pier 1600x1200 (4xAA, 8xAF)
(Source:
Tech Report
------------------------------------------------
7800 GTX - 46.7 FPS
X850 XT PE -
49.1 FPS
6800 Ultra - 36.1 FPS
Far Cry, tr3-pier 2048x1536x32 (4xAA, 8xAF)
(Source:
Tech Report
------------------------------------------------
7800 GTX -
29.3 FPS
X850 XT PE - 24.7 FPS
6800 Ultra - 20.4 FPS
Far Cry, tr1-volcano 1600x1200x32 (4xAA, 8xAF)
(Source:
Tech Report
------------------------------------------------
7800 GTX -
74.7 FPS
X850 XT PE - 71.9 FPS
6800 Ultra - 58.4 FPS
Far Cry, tr1-volcano 2048x1536x32 (4xAA, 8xAF)
(Source:
Tech Report
------------------------------------------------
7800 GTX -
44.2 FPS
X850 XT PE - 30.8 FPS
6800 Ultra - 30.6 FPS
Half-Life 2, trboat 1600x1200x32 (4xAA, 16xAF)
(Source:
Tech Report)
------------------------------------------------
7800 GTX -
73.6 FPS
X850 XT PE - 65.0 FPS
6800 Ultra - 58.7 FPS
Half-Life 2, trboat 2048x1536x32 (4xAA, 16xAF)
(Source:
Tech Report)
------------------------------------------------
7800 GTX -
72.8 FPS
X850 XT PE - 34.6 FPS
6800 Ultra - 23.0 FPS
Half-Life 2, trtown 1600x1200x32 (4xAA, 16xAF)
(Source:
Tech Report)
------------------------------------------------
7800 GTX -
103.7 FPS
X850 XT PE - 93.3 FPS
6800 Ultra - 75.8 FPS
Half-Life 2, trtown 2048x1536x32 (4xAA, 16xAF)
(Source:
Tech Report)
------------------------------------------------
7800 GTX -
101.5 FPS
X850 XT PE - 52.4 FPS
6800 Ultra - 31.8 FPS
Tech Report - "Half-Life 2 is largely CPU limited at lower resolutions on all of the cards, and things only really begin to slow down on the non-SLI rigs at 1600x1200. At 2048x1536, there's a major performance drop for the GeForce 6800 and Radeon X850 XT PE, as well as for the 6800 Ultra SLI rig. The 7800 GTX barely bats an eyelash, providing a most dramatic example of how these GPUs' different peak resolution design points affect performance."
The Chronicles of Riddick: Escape from Butcher Bay 1600x1200x32 (4XAA, 16xAF)
(Source:
Tech Report)
------------------------------------------------
7800 GTX -
45.1 FPS
X850 XT PE - 30.4 FPS
6800 Ultra - 38.5 FPS
The Chronicles of Riddick: Escape from Butcher Bay 2048x1536x32 (4XAA, 16xAF)
(Source:
Tech Report)
------------------------------------------------
7800 GTX -
29.4 FPS
X850 XT PE - 20.7 FPS
6800 Ultra - 18.0 FPS
And no, I'm not an nVIDIA fanboy (or an ATi one either), as I only go for the card that offers better performance during each generation. The X850 XT PE is a nice and fast card, but saying that a X850 XT PE is on par in terms of speed with a 7800 GTX is like saying a GeForce 4 Ti4600 offers similar performance to the 9700 Pro, which clearly wasn't the case back in 2002.