Programmable Gain Buffers or PGBs. These are Op Amps with the gain setting resistors built-in. With a current feedback PGB, like the LMH6739, the feedback resistor is a compromise between the value needed for stability at unity gain and the optimized value used at a gain of +2. The result of this compromise is substantial peaking in some cases at unity gain as you can see here. If this peaking is undesirable, a simple RC filter at the input of the buffer will smooth the frequency response as shown. The graph shows the results of a simple filter placed on the non-inverting input in the schematic to the left.