Takze sbernice je skutecne 256 bit
NVIDIA says this was an error in the reviewer’s guide and a misunderstanding between the engineering team and the technical PR team on how the architecture itself functioned.
a tady se stala chyba v komunikaci.
But the GTX 970 and its altered design has to do things differently. If you walked across the memory interface in the exact same way, over the same 4GB capacity, the 7th crossbar port would tend to always get twice as many requests as the other port (because it has two memories attached). In the short term that could be ok due to queuing in the memory path. But in the long term if the 7th port is fully busy, and is getting twice as many requests as the other port, then the other six must be only half busy, to match with the 2:1 ratio. So the overall bandwidth would be roughly half of peak. This would cause dramatic underutilization and would prevent optimal performance and efficiency for the GPU.
Tedy zapomente na plnych 4GB, protože by se to posralo.
The larger, primary pool is given priority and is then accessed in the expected 1-2-3-4-5-6-7-1-2-3-4-5-6-7 pattern, with equal request rates on each crossbar port, so bandwidth is balanced and can be maximized. And since the vast majority of gaming situations occur well under the 3.5GB memory size this determination makes perfect sense. It is those instances where memory above 3.5GB needs to be accessed where things get more interesting.
If a game has allocated 3GB of graphics memory it might be using only 500MB of a regular basis with much of the rest only there for periodic, on-demand use. Things like compressed textures that are not as time sensitive as other material require much less bandwidth and can be moved around to other memory locations with less performance penalty. Not all allocated graphics memory is the same and innevitably there are large sections of this storage that is reserved but rarely used at any given point in time.
Pro Krtecka, nez zacne priste kecat na moji adresu
All gaming systems today already have multiple pools of graphics memory
The question “should the GTX 970 be called a 3.5GB card?” is more of a philosophical debate. There is 4GB of physical memory on the card and you can definitely access all 4GB of when the game and operating system determine it is necessary. But 1/8th of that memory can only be accessed in a slower manner than the other 7/8th, even if that 1/8th is 4x faster than system memory over PCI Express. NVIDIA claims that the architecture is working exactly as intended and that with competent OS heuristics the performance difference should be negligible in real-world gaming scenarios. The configurability of the Maxwell architecture allowed NVIDIA to make this choice. Had the GeForce GTX 970 been built on the Kepler architecture, the company would have had to disable the entire L2/MC block on the right hand side, resulting in a 192-bit memory bus and a 3GB frame buffer. GM204 allows NVIDIA to expand that to a 256-bit 3.5GB/0.5GB memory configuration and offers performance advantages, obviously. Alternatively to calling this a 4GB card, NVIDIA might have branded it as 3.5GB with the addition of 500MB of “cache” or “buffer” – something that designates its difference in implementation, its slower performance but also its advantages over not having it at all. Let’s be clear – the performance of the GTX 970 is what the performance is. This information is incredibly interesting and warrants some debate, but at the end of the day, my recommendations for the GTX 970 really won’t change at all. It still offers incredible performance for your dollar and is able to run at 4K in my experience and testing. Yes, there might in fact be specific instances where performance drops are more severe because of this memory hierarchy design, but I don’t think it changes the outlook for the card as a whole.
Kauza ukoncena. U soudu s timhle nikdo neobstoji.
For those of you that read this and remain affronted by NVIDIA calling the GeForce GTX 970 a 4GB card without equivocation: I get it. But I also respectfully disagree. Should NVIDIA have been more upfront about the changes this GPU brought compared to the GTX 980? Absolutely and emphatically. But does this change the stance or position of the GTX 970 in the world of discrete PC graphics? I don’t think it does.
