By the way just 2 suggestions whether you face up to such slow loading.
1. Use the option "-noedit" which allows a read-only opening of your layout.
For example: calibredrv -m big_layout.gds -noedit
2. Use also the option "-hideLayers" which hide all the layer by default.
Indeed your are often interested by only few layers like (poly, M1,...) and you don't need to see all of them when you start DESIGNrev.
For Example: calibredrv -m big_layout.gds -hideLayers
If you don't need to see all the layers in the layout then you can use a layer map, and then choose "Only load mapped layers" from the options tab of the file browser.
Layer maps were needed in early versions of Calibre Workbench because we were ignoring datatype. In order to separate datatype you had to map a layer, datatype pair to a new layer. A layer map file is a simple ASCII file that has a layer number, a datatype number and a target layer number
5 2 20 would map layer 5 datatype 2 to layer 20 in Workbench/Designrev.
5 -1 20 would map all datatypes on layer 5 to layer 20.
So for example if you only need to look at layer 5, 9, 10, 11 and you don't use datatypes, the file would look like this:
5 -1 5
9 -1 9
10 -1 10
11 -1 11
This doesn't actually change any layer, but it allows us to check "Only load mapped layers". This will not load any unmapped layers and save on memory. If you use the -noedit or -hideLayers options, we still load all the layers and use the same amount of memory.