IQ w/Shadow Maps On/Off

Another feature you can disable to improve performance is shadow maps. As you know, shadowing can have a profound impact on performance. In order to determine the visual and performance impact of this setting, we turned post-processing back on (since it is normally enabled by default under medium graphics settings) and toggled the shadow map setting on and off. Once again, the screenshots below were all taken with the medium quality graphics setting:

BioShock w/Shadow Maps On

BioShock w/Shadow Maps Off

BioShock w/Shadow Maps On

BioShock w/Shadow Maps Off

BioShock Shadow Maps On


BioShock Shadow Maps Off


As you can see, disabling this setting doesn’t turn off shadows completely. As the manual describes, it is focused on dynamic objects and characters, static objects aren’t affected.

Since the paintings on the floor in the screenshots above are dynamic objects, you can see the shadows they cast with this setting turned on, but the shadows are removed once it’s off. The rest of the shadows in the scene are cast as normal.



BioShock Shadow Maps On


BioShock Shadow Maps Off




What kind of performance hit did we see with shadow maps on versus off?

BioShock Performance 1600x1200x32
Card	Min FPS	Max FPS
GeForce 8600 GTS ShadowOff	26	52
GeForce 8600 GTS ShadowOn	22	49
GeForce 8600 GT ShadowOff	24	46
GeForce 8600 GT ShadowOn	19	42
GeForce 8500 GT ShadowOff	10	18
GeForce 8500 GT ShadowOn	8	17
GeForce 8400 GS ShadowOff	8	13
GeForce 8400 GS ShadowOn	6	13
GeForce 7900 GS ShadowOff	24	48
GeForce 7900 GS ShadowOn	19	47
GeForce 7600 GT ShadowsOff	15	29
GeForce 7600 GT ShadowsOn	12	28
Radeon HD 2600 XT ShadowOff	25	49
Radeon HD 2600 XT ShadowOn	16	35
Radeon HD 2400 XT ShadowOff	9	16
Radeon HD 2400 XT ShadowOn	8	15
Radeon X1950 Pro ShadowOff	30	56
Radeon X1950 Pro ShadowOn	24	54
Radeon X1650 XT ShadowOff	20	33
Radeon X1650 XT ShadowOn	16	32

Notes

We expected disabling the shadow map setting would produce a more substantial gain than post processing beforehand, but other than the Radeon HD 2600 XT that definitely wasn’t the case. If you’re optimizing for more performance and have to choose between one setting or the other you’d probably be better off disabling post processing, especially since it’s likely to annoy some of you anyway.

Now that we’ve shown you a few examples of the various graphics options available within BioShock, we next want to go over the DX9 versus DX10 topic one more time…