We reported yesterday that NVIDIA was having an issue with its GeForce GTX 970 GPU, with its VRAM only maxing out at 3.5GB even with 4GB on offer. Well, this seems to be getting a detailed explanation quickly from NVIDIA, with the Senior Vice President of Engineering Jonah Alben sending PC Perspective a diagram of the reason behind the GTX 970 acting weirdly.
As you can see in the diagram above, there are three four things greyed out. Three SMM blocks and a single L2 cache block. NVIDIA explained to PCPer: "Despite initial reviews and information from NVIDIA, the GTX 970 actually has fewer ROPs and less L2 cache than the GTX 980. 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. That means the GTX 970 has 56 ROPs and 1792 KB of L2 cache compared to 64 ROPs and 2048 KB of L2 cache for the GTX 980".
So the question is, is the GeForce GTX 970 a 4GB card or not? It has 4GB of VRAM, that much we know, but accessing the remaining 0.5GB of RAM is slower than the first 3.5GB.