The Vivace Server doesn't enforce any limit on the update frequency on any single item in RAW mode, so only resource limits could come into play.
However, in the factory configuration, the Server is not tuned for high frequency, but rather for more efficiency, because of the <max_delay_millis> setting of 200 ms.
With this setting, even in RAW mode, for which no filtering is allowed, the Server tries to send data to the client once every 200 ms, then sending all events cumulated over that time all together.

I suppose that this behavior makes you assume that the Server actually filters the updates, which should not happen in RAW mode.
Please try setting <max_delay_millis> to 0 and see what happens.
Anyway, if you have any clear evidence that updates get filtered, we will have to investigate further.