The reason presumably is that Creator 3.0 does a better job at calculating sRAM usage.This means that the 7% figure before likely was not correct, but the 37% one probably is.
Can you tell us more what simple project is using 63% of RAM? maybe post it here?
From Creator 3.0 release notes -
New RAM Usage Calculation
Prior to the 3.0 release, the reporting of SRAM usage at the end of a build with the GNU Compiler
Toolchain did not correctly report the stack and heap settings in the System DWR file. This has been
corrected and PSoC Creator is now properly reporting the RAM usage (note that the actual RAM usage
has not changed, just the reporting in the Output Window). You can modify the Stack and Heap Size
values in the System DWR.
You can adjust the amount of space allocated to heap and stack in the CYDWR file System tab. The tool grabs big chunks to be "on the safe side". What do you guys think better default sizes would be? Enough RAM to make a few nested calls? Enough heap to handle printf reaosnably? We are open for your input because we will probably change this in the next release.
Its too bad you do not have a basic profiler that you could run
a number of projects thru, or a switch in DWR that would allow
trying various settings. Then you could get a "typical" idea of
what real world applications look like.
The only experiences I've had so far with foreign projects are those posted here when there have been problems.
From the mathematical aspect this is not representative, because it excludes all the projects that do not have problems.
What I saw was few stack usage and near-zero heap requirement which totally differs from my personal way of programming ("My name is Bob and I am addicted to frequently use linked-lists and malloc()" ). As Dana mentioned: an easy-to-use profiler that (at least) analyzes stack and heap usage of a project could help to optimize sram usage and would be a big help for us designers.