Last week, Forbes published an explosive story claiming that Nvidia had used GameWorks to cripple AMD’s performance in the new Ubisoft game Watch Dogs. This kicked off a series of events, including our own inability to duplicate similar results and a lengthy conversation with the senior vice president of Nvidia’s content and technology division, Tony Tamasi. Rather than rely solely on these conversations and perpetuate the he-said-she-said nature of the AMD-Nvidia discussion, we decided to take the questions AMD has raised about GameWorks and Nvidia’s counterpoints directly to developers themselves.

We sent out a number of requests for comment and insight to some of the most well-known project heads in the gaming business. Most respondents were only willing to speak off the record, but there were two exceptions: Tim Sweeney, the founder of Epic Games, and Richard Geldreich, a longtime OpenGL developer at Valve (semi-retired as of last week).

The GameWorks discussion has raised many questions about the nature of how game developers and IHV’s (Integrated Hardware Vendors, aka GPU manufacturers) collaborate, whether or not source code is important to that process, whether Mantle and GameWorks should be seen as equivalents, why Nvidia developed GameWorks, and whether GameWorks is a threat to AMD at all.

Because much of the debate over GameWorks is tied to the question of how games are optimized and what that process entails, we’ll start there.

Do AMD and Nvidia need access to developer source code?

AMD: Being able to see and share source code access is very important to our driver optimization process.

Nvidia: Having source code is useful, but it’s just one tool in our toolbox. There are many, many things we can do to improve performance without touching it.

Developers say: They’re both telling the truth.

The first thing to understand about IHV – developer relations is that the process of game optimization is nuanced and complex. The reason AMD and Nvidia are taking different positions on this topic isn’t because one of them is lying, it’s because AMD genuinely tends to focus more on helping developers optimize their own engines, while Nvidia puts more effort into performing tasks in-driver. This is a difference of degree — AMD absolutely can perform its own driver-side optimization and Nvidia’s Tony Tamasi acknowledged on the phone that there are some bugs that can only be fixed by looking at the source.

This philosophical difference of approach makes sense given what we know of the two companies. Nvidia’s graphics business is much larger than AMD’s and the company has invested a great deal of money in creating 3D libraries, rendering engines, programming tools, and in some cases, specialized hardware blocks. AMD hasn’t tended to make as many of these kinds of investments; Mantle is the exception that proves the rule.

Some of this difference in approach is cultural but much of it is driven by necessity. In 2012 (the last year before AMD’s graphics revenue was rolled into the console business), AMD made about $1.4 billion off the Radeon division. For the same period, Nvidia made more than $4.2 billion. Some of that was Tegra-related and it’s a testament to AMD’s hardware engineering that it competes effectively with Nvidia with a much smaller revenue share, but it also means that Team Green has far more money to spend on optimizing every aspect of the driver stack.

Next page: Should developers have access to middleware (GameWorks) source code?