This was posted in Relicnews and seems to work (although, the Steam version might have issues). IŽll copy paste:
To the nice stuff: It's well known that for some reason, Dark Crusade has better load times than Soulstorm, despite the fact Soulstorm was released after DC.
I found a way to counter this, by simply altering the order on which Soulstorm loads its required dll's to resemble the order Dark Crusade's does.
Now I enjoy overall visible faster load times, which is quite enjoyable on large mods
In order for you to get a faster Soulstorm, you will have to edit its executable (don't worry, it's completely safe as long as you don't stray away from the instructions).
And to edit that .exe, you will need the Explorer Suite found here: NTCore.com
Install it, and AFTER DOING A BACKUP COPY OF YOUR SOULSTORM.EXE open Soulstorm.exe with the CFF Explorer.
Now that you opened it, you should see a menu to the left of the window. There, look for "Import Directory". Left-click it.
To the right, there should be a chart with .dll files on the first column, and numbers on the other 6 columns.
What we will do, is basically change the row order, so it looks like this:
Right-click on anywhere on a row and select "Move Up" or "Move Down" to re-order the list.
When you are done, save the changes and... enjoy