Sign in to follow this  

OpenGL vs Direct3D Performance

This topic is 4842 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hi guys, I'm currently going through the OpenGL tutorials on the NeHe site and the DirectX tutorials on the www.drunkenhyena.com site. Now I am running with no hardware acceleration: Savage chipset for a laptop. However the DirectX programs run MUCH faster than their OpenGL counterparts. The difference in performance is striking. Can anyone explain this one? Is DirectX better than OpenGL for non-accelerated platforms?

Share this post


Link to post
Share on other sites
Guest Anonymous Poster
Quote:
Original post by Oluseyi
It's all about the drivers, not the APIs. Even unaccelerated.


Thanks Olusey. Is anyone running OpenGL on a Savage IX8 chipset?
I can't find a Windows XP driver for it that gives anywhere near decent performance. :(

Share this post


Link to post
Share on other sites
Guest Anonymous Poster
Quote:
Original post by Oluseyi
Quote:
Original post by Anonymous Poster
I can't find a Windows XP driver for it that gives anywhere near decent performance. :(
That's because the card sucks. There are lower bounds on these things.


Well, the card doesn't seem to suck too bad for Direct3D, which gives me way higher frame rates (more than double). I don't mean to suggest one API is better than the other but it seems to me that a good OpenGL driver should provide the same performance as I get with Direct3D. Am I wrong?

Share this post


Link to post
Share on other sites
Guest Anonymous Poster
Quote:
Original post by _DarkWIng_
Oh, great.. another OpenGL vs Direct3D. We didn't have one of those for a while now.


Dude, did you read the postings or just the thread title? No one is suggesting one API is better so take a chill-pill.

Share this post


Link to post
Share on other sites
Quote:
Original post by Oluseyi
It's all about the drivers, not the APIs. Even unaccelerated.

That's not entirely true.
The design of OpenGL concentrated on consistency of output (speed wasn't the main priority) - if you draw a triangle, the result should be the same regardless of whether there's a hardware accerator or not and the result should always be the same.
D3D on the other hand focused primarily on speed (as you'd expect since it's designed for game developers) at the expense of consistency. So, that same triangle can look different depending on the what the hardware is capable of or the implementation of the software renderer. The driver writers aren't required to make that triangle look the same as a reference driver.
So, in a software only comparison, OpenGL is limited by the need to produce 'correct' output whereas D3D is free to take shortcuts. However, there are bound to be some software OpenGL drivers that take shortcuts.
And don't forget that driver writers have been known to optimise their drivers for specific games to get good benchmark results at the expense of running other games a bit slower.

Skizz

Share this post


Link to post
Share on other sites
Quote:
Original post by Anonymous Poster
Well, the card doesn't seem to suck too bad for Direct3D, which gives me way higher frame rates (more than double).
Good point.

Vendors tended to have greater competence with one or the other API. Due to the closed nature of device drivers, unless the vendor provides an updated driver you're pretty much stuck.

Share this post


Link to post
Share on other sites
One secret I've found is to install the NVidia detionator drivers even if you don't own an NVidia card. I've had a few laptops where installing those drivers ment the difference between playable and unplayable.

The default OpenGL drivers are rather old, around 97, IIRC. Microsoft hasn't updated them in a while, although they'll be updated for Loghorn in '06.

Share this post


Link to post
Share on other sites

This topic is 4842 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this