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DiRT Rally 2.0 Reviewed

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Have finally started working on... things... and have launched DiRT Rally 2.0 with an NVIDIA GPU (GTX 980 specifically) and the game does not offer CSAA options with it installed.

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CSAA is not a supported feature on Maxwell GPUs such as the GeForce GTX 970 and GeForce GTX 980. 8xMSAA is essentially identical in terms of image quality, and you can probably reduce the performance impact of MSAA by enabling MFAA in the NVIDIA Control Panel. 

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CSAA is not a supported feature on Maxwell GPUs such as the GeForce GTX 970 and GeForce GTX 980. 8xMSAA is essentially identical in terms of image quality, and you can probably reduce the performance impact of MSAA by enabling MFAA in the NVIDIA Control Panel. 

Huh, I wonder why they pulled support from Maxwell. I mean CSAA goes back to the GeForce 8 series. Of course it's hard to think of many games that used it, but I wouldn't think maintaining support for it would be an issue. AMD still supports EQAA and it goes back to the HD6900 series, which is more recent but still pre-GCN.

After my experience with Assassin's Creed Syndicate and MFAA though, I would never enable it. Really can't have entire objects like cranes no longer render, and that's what happened for me.

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While the Maxwell series was marketed as fully DirectX compliant, the cards never performed vary well when async compute was utilized,.. this core feature is in fact exposed by the driver, Nvidia partially implemented it through a driver-based shim, coming at a high performance cost.

 

Unlike AMD's competing GCN-based cards which included a full implementation of hardware-based asynchronous compute, Nvidia planned to rely on the driver to implement a software queue and a software distributor to forward asynchronous tasks to the hardware schedulers, capable of distributing the workload to the correct units, thus requiring that both a game and the GPU driver be specifically coded for asynchronous compute to run concurrently.

 

So basically if a game was not coded to work with Maxwell's static scheduler, asynchronous compute performance took a huge hit, furthermore graphics tasks saturated Maxwell's GPU much more easily than they did to AMD's GCN-based GPUs,.. the driver forces a Maxwell GPU to place all tasks into one queue and execute each task in serial, and give each task the undivided resources of the GPU no mater weather or not each task can saturate the GPU or not.

 

I guess with AMD's GCN-based GPUs being much more heavily weighted towards compute,.. Maxwell-based GPUs were getting smoked in benchmarks and most games were not coded for Nvidia,.. so asynchronous compute was disabled by the driver for Maxwell.     

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I'm unsure what your point about async compute has to do with CSAA (though to my knowledge everything you stated is correct). The technology both predates async compute and is rasterization related, not strictly compute related. In fact, because of how it feeds into the shading process, I wouldn't think it could be done asynchronously.

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My bad Jim, I was looking at some old notes from 2015 about asynchronous compute and Maxwell 2,.. seems there was a lot going on with the GTX 900 family back then, and I got side tracked, went off topic, started blabbing about Async compute.  :blush:

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