Arni, If signal from computer is delivered asynchronously like S/Pdif (Toslink, coax) then in addition to computer clock jitter there would be cable/system jitter. Jitter supressing DACs like Benchmark are always beneficial but not everybody likes the sound. According to technical director of Benchmark John Siau Benchmark DAC1 was not designed to sound warm since warmth (enhanced even harmonics) screws up sound of instruments with complex harmonic structure like piano or percussion instruments. Here is what he says:
"We designed the DAC1 for maximum transparency. If you want to add warmth, you can't add it with a DAC1. Personally, I do not like what warm sounding equipment does to the sound of a piano. Warmth is wonderful on vocals, guitars and certain instruments, but it beats against the streched overtones of a piano. The overtones in a piano occur at slightly higher than harmonic ratios, and these create beat notes with the exact integer ratios produced by electronic equipment (and speakers). Too much harmonic distortion will make a piano sound out of tune. "
"We designed the DAC1 for maximum transparency. If you want to add warmth, you can't add it with a DAC1. Personally, I do not like what warm sounding equipment does to the sound of a piano. Warmth is wonderful on vocals, guitars and certain instruments, but it beats against the streched overtones of a piano. The overtones in a piano occur at slightly higher than harmonic ratios, and these create beat notes with the exact integer ratios produced by electronic equipment (and speakers). Too much harmonic distortion will make a piano sound out of tune. "