AGP 8x slower than 4x on Radeon 9200SE?
"Alex Jackson" <[email protected]>
| Newsgroups | gmane.comp.video.dri.user |
|---|---|
| Message-ID | <[email protected]> |
I've just noticed that setting my AGP transfer speed (via BIOS setup) to 4x rather than 8x results in *faster* framerates in OpenGL apps with my Radeon 9200SE. The speed difference is a nearly constant 20% across the board, regardless of what OpenGL functionality the app uses: glxgears: AGP 4x: ~1900 FPS AGP 8x: ~1500 FPS sdlmame (unthrottled, running pacman): AGP 4x: ~1100 FPS AGP 8x: ~900 FPS Note that these two apps are pretty much at two opposite ends of OpenGL usage: glxgears is all geometry and no textures, while sdlmame is doing nothing but continuously uploading a large texture and rendering it parallel to the screen. I've looked in /var/log/messages and /var/log/Xorg.0.log and it looks like both AGP modes really are using the mode I select; neither is failing and falling back to a slower mode. I'm running stock FC5 with all updates. Does anyone have any idea why AGP 8x yields worse performance than 4x? Does this happen to other people with rv280-based cards (the only chip in the r200 family that supports AGP 8x)? --AWJ-- _________________________________________________________________ Off to school, going on a trip, or moving? Windows Live (MSN) Messenger lets you stay in touch with friends and family wherever you go. Click here to find out how to sign up! http://www.live.com/?mkt=en-ca ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV --