I'm also interested in latency measurements.http://www.michalkaszczyszyn.com/en/tutorials.html
- here are reviews of more than 10 audio interfaces with latency measurement results
Centrance Latency Test Utility is accurate only within 0.5ms. Latency isn't always stable - in some interfaces it drifts (latency jitter). For example - M-AUDIO Firewire 410 has a latency jitter of 0.23ms (10 samples @ 44.1kHz).
There is a more accurate method of measuring latency, that is well described in Cockos Wiki:http://wiki.cockos.com/wiki/index.php/H ... ce_Latency
Using your DAW gives better results as you can signal levels properly and measure with an accuracy of a single sample.
Line 6 POD Studio - on a PC the smallest actual latency is around 15.4ms (WIndows 7 32-bit), on a Mac it's around 7ms... BUT these interfaces can do much more - when you're playing through POD Farm or GearBox standalone you get only about 7ms of latency (300 samples @ 44.1kHz). You can measure this by using another audio interface with known round trip latency - launch the POD Farm standalone app, set up a tone with not too much gain and then measure that other interface latency in with the POD Studio between it's input and output.
Devices such as Line 6 POD XT (2.65ms), POD X3 (1.5ms) and Fractal Audio Axe FX (1ms, tone processing times) are superior to typical audio interfaces as they're equipped with their own processors, memory and they do the job instantly for monitoring while working at a large buffer size with DAW.
I agree that the lower the latency, the better and tighter the groove is. There's another cool thing that you can do - use DI-BOX/splitter (Waves/PRS GTR interface, LittleLabs RedEye, Behringer GIto feed your guitar signal to both recording interface and an analog amp. It's something that I'm experimenting nowadays.
It's important to have a total latency of less than 12ms, but you also have to take into account that sound waves travel through air at the speed of 340 meters per second, so every meter of distance between your ears and your speakers adds 2.941ms of latency.
Anyway here's a brief list of my results (44.1kHz):
Apple Mac mini 2011 built-in audio: 1.904ms (OS X Lion)
ASUS K50IJ built-in audio (VT1708S): 3.7ms (Windows 7)
ESI Maya44 XTe PCIe: 9.932ms (Windows 7)
ESI UGM96: 5.9ms (OS X Lion), 8.7ms (Windows 7)
E-MU 0202 USB: 10.4ms (Windows 7)
E-MU 0204 USB: 9.455ms (Windows 7)
E-MU 0404 PCIe: 6.2ms (Windows 7)
E-MU 1616M PCIe: 6.077ms (Windows 7)
Focusrite Saffire PRO 14, 3.741ms (Windows 7), 5.011ms (OS X Lion), MixControl 3.0
Focusrite Saffire PRO 24, 4.399ms (Windows 7), 5.714ms (OS X Lion), MixControl 3.0
Line 6 POD Studio: 15.4ms for DAW, 6.8ms for monitoring through the POD Farm/GearBox standalone
Line 6 POD XT: 2.65ms hardware monitoring through XT, more than 12ms for DAW
Line 6 POD X3: 1.5ms for hardware monitoring through X3, more than 12ms for DAW
M-Audio Firewire 410: 6.077ms (14 samples, Mac OS X Lion)
Peresonus Firestudio Mobile: 4.739ms (Windows 7), 6.077ms (14 samples, Mac OS X Lion), Universal Control 1.6
TC Electronic Konnekt 6: 4.693ms (Windows 7), 6.031ms (Mac OS X Lion), TC Near 3.0 f22
Not all of these values are easy to achieve and stable, read more on my website:http://www.michalkaszczyszyn.com/en/tut ... l#database