While the main aim of Terra Slicer is to alleviate memory issues by allowing you to use the generated slices with streaming solutions (like our S.A.M. product), we cannot gaurantee that you will see an improvement in performance. The following breakdown should give you an idea of whether you will see a performance improvement, though please note these are general guidelines and may not be true in all scenarios.
Benefits generally boil down to the following three areas.
1) Higher FPS
2) Lower RAM/memory usage
3) Faster Editor Performance (working on your game is faster).
Keep in mind that the general idea behind streaming solutions (such as S.A.M.)
and Terra Slicer is to break your Game World down into smaller slices and chunks,
so that you can load only the portions of the game world that are needed at
any given time, both in editor and at runtime.
For larger game worlds (ones with more objects/assets, not necessarily larger
in physical dimensions), there is more of a benefit to be had.
Think of it like this:
The total size (in terms of number of assets) you load with a streaming solution
will remain relatively fixed (after experimenting to find the right amount).
However, the total size of your game world will likely grow as you add new areas
and such. If we imagine a formula for calculating the benefit you will receive, it
would like this:
Benefit = Total Game World Size / Streaming Load Area Size
So the benefit will grow if the total game world size increases or the area
you are streaming in one moment decreases.
If the two are close to the same size the benefit will be small. This is why
you might not see much benefit between a 1000 x 1000
terrain with no other objects and 4 sliced terrain (each 500 x 500). The load
area in this case is exaxtly the same as the total size of the world.
Terrain wise, you also need to take into account that each Unity Terrain has
overhead. Each uses extra memory and reduces FPS by a bit.
Slicing can offer the following benefits, but only in certain situations:
1) If the region of slices you load is smaller than the original terrain sources size, the FPS MAY be better and memory usage lower. Reference the benefit formula I posted above. Also bear in mind that in genereal Unity splits drawing operations
between different Terrains. This can result in multiple terrains using more Draw Calls than a single Terrain, which may negatively impact performance.
2) The integration of the terrain into the main thread (when it is loaded)
will cause less of an FPS drop the smaller the slices are. This is only a benefit
if you use streaming though. If your source terrain starts in the scene already loaded
this does not matter.
3) Since terrain have a max resolution, if you use a single terrain you are locked to a max resolution (around 4096). Slices allow you to combine multiple terrains together to create game Worlds of higher resolutions.
4) Using slices allows you to change out the textures to support different
biomes while keeping the texture count low. On a single terrain you may need 16+ textures.
Using slices you might be able to get away with 4 different ones per terrain (although note, some textures will need to be shared between neighboring terrain in order for them to blend into each other.
In conclusion, I hope you can see how difficult it is to predict whether someone
will see benefits while using Terra Slicer and a streaming solution. While it is likely,
there is no guarantee.