G400 OpenGL drivers not supporting AGP Texturing ?

[Gavin]

Hi,

Take a look at http://www.reactorcritical.com/perfo...quake3_5.shtml , specifically at this quote:

"In 32 bits (for both the framebuffer and textures) this size of textures increases dramatically that affects the speed of 16 MB boards. On the TNT2 at 800x600x32 the speed is halved. Owners of 16 MB Rage128, TNT2, and G400 boards can't use 32-bit textures. Please note that it is possible to use 16-bit textures in a truecolor mode.

So why the speed drops so much when there is no enough texture memory? The reason is that the OpenGL drivers for the rage 128, TNT2, and the G400 do not support AGP-texturing, so textures have to be loaded into the local memory, and the process is very slow."

So, when will this be built into the drivers ?? I am curious to know....

[paulcs]

Isn't this a hardware limitation? If so, the cure would be to buy a board with 32 MB of RAM.

Paul
paulcs@flashcom.net

[Nuno]

So why the speed drops so much when there is no enough texture memory?

Because doing AGP texturing is much more slower than rendering in the video memory. On the G400/Max you have 168/200Mhz SGRAM memory in a 128 bit bus. The system RAM is mostly 100 Mhz SDRAM with a 32/64 bit bus.

So isn´t it clear why even the G400, wich has a superb AGP implementation (AGP 2x DIME), takes a nose dive in performance if it runs out of memory and has to do AGP texturing?

Oh and *I think* AGP texturing is definitly on, if it wasn´t there wouldn´t be a drop in performance, there would be a slide show if a card run out of video memory and has to swap textures over and over.