Sanderxpander
I'm fine with not knowing because I don't want to buy that card, it's just important to state if it's real latency or reported latency. If you want to know the real latency, play back a mono track (preferably something percussive) out of one of your outputs and record it (also mono) through one of your inputs (be careful to disable monitoring). Now put the tracks next to each other, zoom in and see how many samples the rerecorded one has shifted.
That is not testing RTL, that is testing Sonars Offset adjustment which is based on the driver reporting the RTL. Most good ASIO drivers will get this bang on and nothing to worry about, But this test with the same interface using WDM ,WASAPI or MME will result in the offset being out and sometimes by a lot.
Almost any interface will report low RTL figures at 64 buffer,,,, but is your system stable? Do you get drop outs or crackles? This is the big difference in quality drivers/ firmware of interfaces. And it certainly helps to be running a powerful optimized computer system. And don't forget those "hidden" buffers most interfaces under $500 seem to sport.
At what RTL is your system stable? Nothing else means diddly squat. I can get 3.4 ms with my Scarlett but it will result in drop outs.
a Stable system @ 7ms is par for the course with the under $500 price point.
And note that this test as shown above does not differ in results at ANY buffer setting. And for me it did not differ between both tmy Tascam and my Scarlett interfaces. But interestingly the Scarlett does not seem to support WDM or MME mode for me so I used the Tascam.