You can read about Benchmark's technology here: http://www.soundonsound.com/sos/jul05/articles/benchmark.htm
As far as I remember at 50GHz most of samples are redundant. This frequency is not real (1 million times oversampling) and is based on statistical manipulations(finding exact spot for the output sample).
They also mention updating output DAC at only 110kHz. Most of DAC chips have higher THD at 192kHz than 110kHz.
Asynchronous upsampling never brings exact oversampling ratios. If specification says 4x,8x,128x etc. then it is not asynchronous upsampling converter but rather oversampling one based on PLL (phase lock loop).
As far as I remember at 50GHz most of samples are redundant. This frequency is not real (1 million times oversampling) and is based on statistical manipulations(finding exact spot for the output sample).
They also mention updating output DAC at only 110kHz. Most of DAC chips have higher THD at 192kHz than 110kHz.
Asynchronous upsampling never brings exact oversampling ratios. If specification says 4x,8x,128x etc. then it is not asynchronous upsampling converter but rather oversampling one based on PLL (phase lock loop).