Having 24-Bit Sound or not

I have a MacBookPro. I connected my laptop to Benchmark DAC1 HDR by USB. In these conditions do I have 24-Bit music or not ? My DAC is in accordance with 24-Bit but my concern is can my laptop give 24-Bit to DAC by USB.

Thank You,
The answer is YES. Connected via the USB the Benchmark is true 24 bit native.Your Mac book can output that.
The file you are playing has to be a 24 bit recording. If it is 16 bit you will get 16 bit
Go to Applications/Utilities/Audio MIDI Setup

You can set the bitrate and sample rate in there. I think the HDR is limited to 24 bit/96kHz (no 192kHz) and it is synchronous USB, so it isn't as good as a proper async USB connection.

One of the problems with the OSX audio API is that stays that way after you set it. Irrespective of the sample rate and bitrate of the files you are playing. Resampling sometimes isn't the best quality.

You can download a reasonably cheap app from the appstore called BitPerfect which allows iTunes to switch the sample rate on the fly. It does a fair bit of what more expensive apps like PureMusic, Amarra and Audirvana Plus does, such as loading the entire file into memory before playback etc.

I prefer Audirvana Plus because it supports DSD playback.
I downloaded BitPerfect this week - easy install, with a good online manual.

I noticed a more dynamic presentation with better detailed highs and better sivilance presentation - I assume this is because there is no up sampling taking place.

I wanted iTunes to stream just the content of the music file whether it's 16/44 or 24/96 and that is what appears to be happening - not as before where iTunes streamed everything at 24/96 according to the readout on my DAC

And only $9.99 from the apple store

I've since changed to Audirvana since it bypasses all of the Apple software and provide a significant improvement in audio quality over BitPerfect