Originally Posted by brucethemoose
That's not really a gaming feature, system RAM is too slow for the GPU to use.
Where did you hear that it was?
No it isn't.
You're thinking about streaming in textures leading to GPU stalls (how things have been done thus far). That's not how Vega works. Rather than pausing the GPU in order to stream in textures (or using Asynchronous Compute in order to allow streaming in parallel with other work on the GPU), HBCC retains all of the required and most frequently accessed information in the framebuffer and then can stream and access data residing outside of the framebuffer, on any storage device, without incurring a GPU stall. That means that the GPU never pauses, ever, utilization would be (most likely) in the 90+ percentile at all times (hence the tachometer AMD is introducing on the GPU).
So no, system RAM is no longer "too slow", neither would a hard drive or SSD be too slow and yes... this is a gaming feature. A +50% performance boost (avg FPS) and a +100% performance boost (min FPS) was claimed by AMD in Deus Ex due to this feature (this feature alone... we're not talking about any other changes in Vega here).
Yeah... Vega is not gunning for Pascal, it is gunning for Volta.
Not sure was a GPU stall due to memory overcommitment is?
GPU video memory is a limited resource. In DirectX 11 and OpenGL the application is allowed to overcommit video memory without crashing. Overcommitment means allocating more memory than is physically available. However, just like with CPU memory, this forces the OS and the graphics driver to start paging the memory in and out of VRAM which is as slow as it sounds! If a rendering operation is dependent on a non-resident resource, the GPU will have to stall, and these stalls can take a long time. Therefore you should never rely on video memory paging. Instead; query the GPUs memory size and use this to limit the amount of requested resident data. Please be aware on PC there are always other users of VRAM so budget your application appropriately.
With Vega, this is no longer an issue.
The second case is Texture Data Transfer related: http://www.crcnetbase.com/doi/abs/10.1201/b12288-35
Of course Asynchronous transfers only allow one way, at a time, bi-directional transfers. HBCC allows seamless streaming... two way bi-directional transfers.
I think you can see what this means.Edited by Mahigan - 4/18/17 at 6:14am