Poor performance in 1400x1050

[mgm]

I'm running RH8.0 on an Inspiron 8100 with a Geforce2 Go, and the 3123 driver. The display's native res is 1400x1050, and I've got this working fine (worked out of the box with Xfree 4.2.0 and 3123).

But, I've noticed some of the OpenGL screensavers (Atlantis or gears, for example) are unbelievably slow. I get frame rates of like 1fps. I've tried various things, including verifying libs as mentioned in appendix C of Nvidia's README, but to no avail.

But here's the weird part... First, if I run the the screensaver app in a window, from the commandline (instead of letting it run as an actual screensaver) it runs at the right speed. And, even weirder, I noticed, accidentally that everything runs great if I run X in 1280x1024 rather than 1400x1050.

What gives?!?! Is there something inherently bad about 1400x1050?

--mgm

[Andy Mecham]

What color depth are you running at? How much video memory do you have?

--andy

[mgm]

That's at 24bpp and I have 16Meg Video RAM

--mgm

[Andy Mecham]

You're running out of video memory.

At that resolution, you're using a minimum of

1400*1050*4*3 = 17640000 = 17.6MB of memory.

As this exceeds your available video memory, you're falling back to software rendering.

--andy

[mgm]

Oh. Duh. Good point!

Thanks,
--mgm

[mgm]

Hey, wait...

1400*1050*4*3 = 17640000 ...

1400x1050 pixels, gotcha...

3 Bytes per pixel, gotcha...

But, where does the 4 come from? Is 4X the RAM needed for the hardware manipulation? (Just curious. I'm not a graphics hardware guru, nor much of a gamer...)

Thanks,
--mgm

[Andy Mecham]

4 == bpp
3 == number of buffers you're using (front, back, depth)

--andy