Table 10.

Dependence of simulation performance P, cutoff settings, and total power consumption on the graphics processing power for the RIB system on a node with 2 × 2680v2 CPUs and up to 4 GTX 980⁺ GPUs.

Installed GPUs	P (ns/d)	Tot. power draw (W)	Cutoff (nm)	Cost ratio short range	Cost ratio PME 3D FFT	Energy efficiency (W/ns/d)
0	1.86	446	1	1	1	240
1	3.99	622	1.16	2.6	0.65	156
2	4.69	799	1.38	3.75	0.46	170
3	4.85	926	1.45	4.22	0.42	191
4	4.96	1092	1.61	5.36	0.36	220

The “cost ratios” indicate the floating point operations in this part of the calculation relative to the CPU‐only case.