It depends on where you buy them, I have seen sub 10kpps galvos sold on ebay as 30kpps gavos.
You can spot these by their rectangular mirrors (mass limits quick changes in direction so generally faster galvos will have smaller mirrors and those with rounded/chopped corners).
You can also identify them by checking the wiring between the galvo amplifier and DAC (i.e. the lasershark). If the X and Y inputs only have two wires, the amplifiers aren't interpreting a bipolar differential signal which is important for position stability and to prevent distortion at higher frequencies.
Don't forget the ILDA test pattern is supposed to put a little stress on your system too.. otherwise it wouldn't be a very good test pattern
If your galvos aren't making terrible noises but you still see distortion it is possible your galvos are not tuned to be in harmony with OpenLase's default settings. Tuning can be performed in two spots...
1. The galvo amplifiers have a bunch of multi-turn pots which impact the galvo amplifier control loops.
2. If you look towards the top of some openlase executables you will see they have custom tuning attributes. playilda does not use custom settings, but the simple.c example does:https://github.com/marcan/openlase/blob/master/examples/simple.c#L87
When you tune a system, remember that you are tuning it according to your current setup.. i.e. if you have adjusted the output size/keystoning/kpps rate in the output app, tune the ilda output, and then adjust the output size/keystone-ing again.. you will have to re-tune the system!
Also keep in mind that while you can get close, it is unlikely you will ever get a perfect ilda test pattern.http://www.laserist.org/StandardsDocs/ILDA_TestPattern95_rev002.pdf