GRUxTSAR :
VincentP :
GRUxTSAR :
VincentP :
Two GTX 970 cards in SLI will give you this frame rate, but I would have concerns about having only 4GB of VRAM in the long term.
Ideally I would suggest you wait for 8GB models to be released.
Two GTX 780 6GB cards in SLI would be the next best thing available at the moment.
A core i7 4790K and a Z97 motherboard, 16 GB of DDR3 memory in a 2 x 8GB kit.
Either way you won't be getting 4gb with the 900 series. The memory bus will bottleneck the VRAM usage. You'll be getting ~3gb of 8gb unless you cool your GPUs with liquid nitrogen and can set the memory clock to 1000000000000mhz
That is rubbish.
The width of the memory bus has nothing to do with the total quantity of VRAM.
The GTX 780 3GB version and 6GB version had the same memory bus. Adding extra VRAM doesn't make the VRAM faster or slower, it just allows the GPU to store more in VRAM.
An 8GB version of the GTX 970 or 980 will simply have more memory chips. It will be the same speed, but the additional memory will allow more capacity for textures, frame buffer, etc.
But your VRAM usage will cap long before you hit 8gb. A 256 bit bus will NOT utilize 8gb
Having 4 GB or 8 GB of VRAM has nothing at all to do with the 256 bit bus.
Having a wider bus allows you to access memory faster not have more of it.
The number of bits in the bus is the number of bits you can read from memory at one time.
The speed is also affected by the memory frequency and compression used.
Nvidia and AMD have moved from a 384-bit bus to a 256-bit bus in recent cards (GTX 970, GTX 980, R9 285) because it has allowed them to save power and reduce cost. They have compensated for this by using faster clocked memory and better compression.
To include more memory they need only fit it on the PCB, attach it to the existing memory bus, power it and keep it cool.
They could easily include more memory on every card in the range but it affects cost so they try to balance the provided memory size with the expected usage of the card based on the performance of the GPU.
Workstation cards typically have more memory because of the applications these run, and because cost is less of a factor. The K6000 for instance has 12 GB of VRAM and it still has a 384-bit bus. In the lower end of the range, the K2200 has 4 GB of VRAM and a 128-bit memory bus.