In patch http://gerrit.ovirt.org/#/c/35281, it seems that the REST API is calling a query *per VM* in order to re-populate the display-related values. 

This will potentially overload the engine, especially if we are planning to move the GUI to work over the REST API and request VMs every 5 seconds (by default) per client, as we are doing today. 

Improvement suggestion from Juan [1]:
"""
I'd suggest to implement at least a query that takes multiple VM identifiers and returns the graphics devices of those multiple VMs. This would allow for a 1+1 queries scenario, instead of 1+N. Once the backend provides this the RESTAPI can be changed to use it.
"""

[1] http://lists.ovirt.org/pipermail/devel/2015-February/009900.html