IHV-specific Enhancements in Games

We work with the developer to improve the performance on the title, that means altering the rendering characteristics and shader programs; likely the native application render characteristics would improve for everyone. I suspect that NVIDIA's complaint stems from a patch coming out that alters the shaders and knocks the detection of some specific shader replacements out of whack.

 

Dave, how can you be so sure that a given change that improves performance on AMD hardware will benefit the competition as well? What sort of changes typically go into these patches?

Also, AMD often releases performance drivers to target specific games. I'm assuming those drivers don't do shader replacement. So why would nVidia's drivers need to?

 

Dave are there any articles about what exactly a devrel does in optimizing a game

ps:
"specific shader replacements"
should devrel's be replacing shaders ?

pps: similar to trinibwoy's post
the swine ninja posted me

 

Swoosh!!

 

A decade of drivers having to clean up the AA mess for developers says yes.

 

Yeah I don't see what's wrong with replacing shaders as long as image quality doesn't decrease. I also assume AMD, like Nvidia, replaces shaders whenever possible.

 

I googled shader replacement and found these choice quotes

 

Which in turn, led me to this.

Ah the good old days. Rys beginning his detective work on invSqrt, a heated debate on shader replacement, benchmark philosophies, Chris. Good times.

 

from that link
anyone explain this
"I doubt it but ati or nvidia could pay out $250k and do it themself ( well thats how much it is for a IHV to mod the Q3 engine )."

 

IIRC, the first id Tech licensees used to be the IHVs, plus intel before they were into graphics, etc. id had this license option that was cheaper but they weren't allowed to do any commercial releases. So basically, if they really wanted they could compile new binaries for id's games that were optimised for whatever they were trying to show off. IIRC, again, I believe there were AMD optimisd DLLs for Quake 3. This was back when they were pushing the 3DNow! stuff. AFAIK, Intel still uses licenses for their raytracing ports of the id games.

EDIT: Oh and I originally forgot to mention this but, from that thread:

So yeah, take that random internet dude.

 

In this instance the driver guys had analysed what the app was doing and picked out inefficiencies (unnecessary draw calls, flushes, etc.) and fed that back through to the ISV team to discuss with the developer. So in this instance the native app render performance would be improved.

 

So you're saying you don't purposely get the dev to implement effects/code that benefits from the GCN arch at the expense of Nvidia's due to their lower compute power?

 

Well Dave, you just admitted that AMD works with the developer to "alter the shader programs" in the game code so that performance improves with AMD hardware. So it hardly makes sense to vilify NVIDIA here.

When Crystal Dynamics issued the first Tomb Raider patch (with NVIDIA primarily assisting in the background), performance and stability improved on Geforce cards without negatively affecting performance and stability on Radeon cards. So for end users, this was one step forward and zero steps back. When Crystal Dynamics issued the second Tomb Raider patch (with AMD primarily assisting in the background), performance improved on Radeon cards but not without negatively affecting performance on Geforce cards. So for end users, this was one step forward and one step back. Like I said earlier, I do still believe that Crystal Dynamics is largely at fault here. They should never have released a game that was unstable for a large percentage of their user base, and they should never have released a "patch" that improves performance for some while degrading performance for others.

 

I completely agree. Even if AMD's assistance with Tomb.Raider was general shader work that without nvidia game specific optimizations might have helped them too, Crystal must have known from QA that Nvidia was adversly affected and worked with them to.resolve those issues before release.

 

Or perhaps it means AMD aren't as aggressive with wholescale shader replacements in the Driver, thus things don't break as often when shaders in games are adjusted.

Regards,
SB

 

There's a big difference between patch fixing known problems with x cards and patch improving perfomance with y cards, which likely is fixable on x cards via driver adjustments