How can I improve speed of select?
Your where condition that checks for equality for utcdt converted to a date is SARGable, but uses a dynamic seek.


  The problem is that these hidden implicit conversions can result in inaccurate cardinality and distribution estimations at any stage of the plan.  So, even if you get a seek, the plan might be way off overall. - Dynamic Seeks and Hidden Implicit Conversions - Paul White


Try converting your where condition to an explicit range and see if there is any improvement:

select *
from Tick.X_H
where Symbol = 'donkey'
  and utcdt &gt;= convert(datetime2(7),'20110102')
  and utcdt &lt;  convert(datetime2(7),'20110103')


Based on this answer by Martin Smith the explicit range may reduce unnecessary reads.

References:


Dynamic Seeks and Hidden Implicit Conversions - Paul White
Cast to date is sargable but is it a good idea?
SARGable functions in SQL Server - Rob Farley