The GTX 780 Ti and the GTX 980 use identical memory technology, but since the width of the memory interface on the GTX 980 is only 2/3 that of the GTX 780 Ti memory interface, memory throughput is likewise only 2/3. Abstracting from this particular case: Generally speaking, over the past ten years the memory bandwidth of GPUs has increased more slowly than the FLOPS, so for use cases where there is a choice, leaning towards increased computation and reduced memory accesses is usually a good way of future-proofing one’s code.
[url]http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-780-ti/specifications[/url]
Memory Interface Width 384-bit
Memory Bandwidth (GB/sec) 336
[url]http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-980/specifications[/url]
Memory Interface Width 256-bit
Memory Bandwidth (GB/sec) 224