Driven by performance, cost and what information you can get, a typical ECU runs at 180 Mhz, they are only 32 bit, with usually 128KB of RAM and between 2 and 4 MB of ROM, compare that to a PC?? (3-4 GHZ clock, 64 bit..etc)
So, memory and processing time is a premium, what you need to run the engine, transmission..etc runs usually at 10 ms or event based as shown above (could be 2 ms loop time) but what is not essential will run slower, but still enough information for the dealer or the warranty service.

 

I'm not doubting you, cause I don't know. But my 94 Miata LINK ecu ran at 10hz and was too slow to tune the engine past basic boosting and timing levels. Not to mention, poor boost control. And the PASM on the .1 cars only respond at 10hz which is far outdated and replaced with much faster units...

Just find it ridiculous that the ecu would run that slow.

Cw