16/32 bit colors question

I was playing CSS and I notice that on 16 bit color, max setting I get 120-140fps. But on 32 bit color, max setting I only get 40-60fps.

Why the huge drop in performance, is this normal?

I have 7900gs.

 

The drop in performance has nothing to do with the change in color depth. All modern GPUs natively render in > 32bpp precision. You must've selected a framelock (such as vsync or a simple 60hz frame cap) when you changed to 32-bit rendering.

 

thanks for the answer

 

They might do so natively but if a user manually changes the option for a game to 16-bit then it will be rendered at 16-bit.

As to why you might get better performance is maybe because there are less colors to render.

 

Regardless of what bit-depth the application calls for, the GPU is going to render it at 32bpp (or greater) internally, and then dither down to 16bpp when requested. There are no fewer calculations being performed just because the app wants lower precision. This has been true of all NV & ATI GPUs released since the very first DX9-compliant cards came out in 2003.

It hasn't been a performance issue since the days of the original Geforce in 1999.

 

Actually, some older games run better in 16-bit, but it just looks awful. (You should really be able to run old games in 32-bit).

 

techguy2k7 wasnt saying that it wont display at 16bit color. he is saying that reducing the color depth will have no performance impact, period. ur graphics card is still going to render at 32bit color but it will display at 16bit color. no performance gains at all.