Far Cry was the first title to adopt High Dynamic Range (HDR) rendering via floating point blended surfaces, however its support was specific to NVIDIA's range, as these were the only boards with such capabilities when it was implemented, which limited use on the new X1000 series. CryTek, the developers of Far Cry, have implemented a patch that not only changes the engine to support ATI's floating point blending capabilities, but also adds the capabilities for multi-sampling FSAA with HDR.
Far Cry - HDR Performance  
| |
307200 |
480000 |
786432 |
1310720 |
1920000 |
| X1900 XTX |
28.0 |
43.7 |
71.3 |
107.5 |
117.1 |
| X1900 XT |
27.9 |
43.6 |
70.5 |
104.2 |
111.7 |
| X1800 XT |
28.0 |
43.6 |
68.8 |
85.7 |
87.9 |
| X1900 XF |
27.9 |
43.7 |
71.5 |
116.3 |
142.3 |
| X1800 XF |
28.0 |
43.7 |
71.1 |
107.7 |
115.0 |
resolution x fps - Mpixels per second
Far Cry - HDR Performance Diff
| |
640x480 |
800x600 |
1024x768 |
1280x1024 |
1600x1200 |
| X1900 XTX to X1900 XT |
0.40% |
0.20% |
1.00% |
3.10% |
4.80% |
| X1900 XTX to X1800 XT |
-0.10% |
0.20% |
3.50% |
25.30% |
33.00% |
| X1900 XF to X1800 XF |
-0.10% |
0.00% |
0.50% |
7.90% |
23.70% |
Far Cry - HDR Performance Crossfire Increase
| |
640x480 |
800x600 |
1024x768 |
1280x1024 |
1600x1200 |
| X1900 |
-0.20% |
0.10% |
0.40% |
8.20% |
21.50% |
| X1800 |
-0.20% |
0.20% |
3.30% |
25.70% |
30.70% |
percentage
The performance difference between the X1900 XTX and XT is roughly where we would expect it to be, given the theoretical differences between the two. Comparing the X1900 XTX and X1800 XT a 33% performance difference can be seen, which is beyond either their pixel or bandwidth theoretical differences. Although we may expect rendering to an FP16 buffer, as each pixel is twice the size of a normal 32-bit pixel, to be bandwidth limited, it appears that X1800 was slightly shader bound when rendering with HDR, which is alleviated with X1900.
The X1900 Crossfire platform also gains around 24% on the X1800 Crossfire platform at high resolution, with the average rendering performance being well above 60 FPS at 1600x1200.
Far Cry - 4xAA 8xAF HDR Performance
| |
307200 |
480000 |
786432 |
1310720 |
1920000 |
| X1900 XTX |
27.6 |
43.0 |
60.3 |
70.3 |
73.2 |
| X1900 XT |
27.8 |
42.6 |
57.7 |
66.6 |
69.3 |
| X1800 XT |
27.7 |
41.6 |
53.9 |
60.9 |
58.4 |
| X1900 XF |
27.6 |
43.2 |
70.7 |
98.2 |
103.5 |
| X1800 XF |
27.7 |
43.1 |
69.0 |
87.8 |
86.0 |
resolution x fps - Mpixels per second
Far Cry - 4xAA 8xAF HDR Performance Diff
| |
640x480 |
800x600 |
1024x768 |
1280x1024 |
1600x1200 |
| X1900 XTX to X1900 XT |
-0.60% |
0.90% |
4.50% |
5.40% |
5.60% |
| X1900 XTX to X1800 XT |
-0.10% |
3.30% |
12.00% |
15.10% |
25.30% |
| X1900 XF to X1800 XF |
-0.10% |
0.40% |
2.40% |
11.80% |
20.40% |
Far Cry - 4xAA 8xAF HDR Performance Crossfire Increase
| |
640x480 |
800x600 |
1024x768 |
1280x1024 |
1600x1200 |
| X1900 |
0.10% |
0.70% |
17.10% |
39.80% |
41.50% |
| X1800 |
0.00% |
3.60% |
28.10% |
44.00% |
47.20% |
percentage
There is a similar scenario as the previous test when both 4x FSAA and 8x AF are enabled with HDR, except that this time the X1900 XTX is a little more bandwidth limited, so the performance advantage it has over the X1800 XT is cut down a little. With this scenario being more bandwidth limited the gains for the Crossfire platforms are larger. |
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