This is a list of interfaces tested for Interfacing Linux. System configuration information can be viewed here.
USB
Apogee ONE (2009)
Behringer FCA1616
Digidesign Mbox 2 Mini
Douk Audio U2 USB
Focusrite Scarlett Solo (Gen3)
MOTU M4
PreSonus ioStation 24C
US-TASCAM 16X08
FIREWIRE
Apogee Duet (2007)
Behringer FCA202
Behringer FCA1616
Digidesign Digi 003R
Focusrite Saffire Pro 40
M-Audio 2626
MOTU 828MKII
MOTU 828 MKIII
MOTU Traveler MKI
Phonic Firefly 202
Presonus Firestudio 26×26
PCI/e
Digigram VX222e
RME HDSP 9632
RME AIO Pro
Busted
Digigram VX222v2
Behringer UV1
Linux Audio Interface Benchmarks
While many kinds of audio latency metrics exist, one useful and well-understood metric is round-trip latency; the time it takes for an audio signal to enter the input of a device, get processed, and exit the output.
The following measurements were taken using jack_iodelay.
USB Round-Trip Latency

Firewire Round-Trip Latency (FFADO)

PCIe Round-Trip Latency

Jackbox Testbench
CPU | AMD Ryzen 5600G |
RAM | Corsair Vengeance LPX 16GB |
Motherboard | MSI B550-A PRO |
GPU | NA |
Storage | Silicon Power 256GB NVMe |
PSU: | EVGA 600 B1 |
Firewire: | StarTech PEX1394B3 |
Network: | Mellanox MCX311A-XCAT CX311A |
OS: | Debian 12 (Bookworm) |
Kernel: | 6.1 RT |
Desktop: | XFCE 4.18 |