You might also want to [set ( values to be displayed by your slider or number box.
i.e. better this
[your input] | [set ( | [vslider]
rather than
[your input] | [vslider]
When a slider receives a [set $1( message, it only displays the data, without executing any output. This is another good resources-saving method. Obviously we are talking about a situation in which you want to use a good amount of sliders and nboxes. Otherwise, as noted previously, one or two sliders do not really represent an issue.
Hiding massive GUI works also in my experience. cheers,