Intel Questasim is very slow for changing directory & compiling

[FabianL]

I have a similar problem to this: https://community.intel.com/t5/Intel-Quartus-Prime-Software/Intel-Questasim-is-very-slow-e-g-cd/m-p/1452108

The Simulation runs very fast, but every time I change directory (regardless what's in it) questa gets stuck for no reason and also with no significant load:

Other commands which interact with the filesystem, e.g. "dir" run fast.

Same happens when I compile any VHDL file. The compilation itself runs fast but Questa freezes for several seconds before compiling  every single file and also after the compilation is complete (in transcript window).

The delay and freezes do not differ between Start and full FPGA Edition. Im using a full license for FPGA Edition.

• Questa 2021.1
  • runs fast (Starter & full version)
• Questa 2022.1 
  • runs extremely slow
• Questa 2023.4
  • runs extremely slow
• Questa 2024.1
  • runs extremely slow
• Questa 2024.3
  • runs extremely slow

Freezes during changing directory would be acceptable, but freezes for every single file compilation make it completely unusable! 

I would be thankful for any solutions. 

best regards

Fabian

[RichardTanSY_Altera]

I would like to clarify what you meant when you said you changed the directory — were those project directories, and did you copy everything from the original directory into a new one?

Why do you want to change the directory?

What files are inside the directory?

Does the slowness still occur if you start everything from scratch — for example, by removing modelsim.ini, library files, or any other files that might have been generated by the simulator tool?

Additionally, which OS are you using? 

If the issue still persists, please provide a test case and steps to duplicate the issue. 

Regards,

Richard Tan

[FabianL]

Hello Richard,

I'm using Windows 10 22H2

Steps to reproduce:

• I am starting Questa from scratch by simply starting the start menu shortcut with its default working directory. (on my machine it is D:\intelFPGA\25.1.1_pro\questa_fe\win64)
• I change directory to any other directory. The target directory does not contain a modelsim.ini
• But I may also change directory to my actual working directory which contains the attached modelsim.ini. 
• The slowness occurs before I even start any compilation nor simulation

Best regards

Fabian

[RichardTanSY_Altera]

How long do you experience the freeze when changing directory?

Are all the Questa versions you have installed bundled with the Quartus Pro Edition?

Do you observe the same behavior with Questa bundled with the Quartus Standard Edition?

From my side, it took roughly 40 seconds to read the modelsim.ini file when changing directories using a laptop.

However, on a more powerful machine, the loading time was significantly shorter — around 10 seconds.

If possible, try switching to a different machine and see if you observe the same behavior.

Additionally, consider restarting your current computer to see if that helps.

Regards,

Richard Tan

[FabianL]

Hello Richard,

• I have the same situation with both Pro & Standard bundled Questa versions
• 40 seconds for changing a directory is exactly what I mean, that this is not what it should take. I have a high performance workstation with i9 13th generation, my directory switching time is a bit shorter, but I guess changing a directory or reading an .ini File should be a top notch task for a workstation like this.
• Especially since it was much faster in previous version (Questa 2021). I have attached measurements for Questa 2021 & Questa 2025 with a .do file for reproducing the results. (log_Questa_2025.1.txt  vs log_Questa_2021.1.txt )
• I also have significant delays after compiling files and starting simulation. I created a sample project (questa_test.zip) with a compile script which logs the timestamps after compilation and before/after simulation. For Questa 2025.1 the time after compilation before starting simulation nearly doubled! compile_log_Questa_2025.1.txt vs compile_log_Questa_2021.1.txt

I hope this helps to reproduce the issue on your side.

By the way restarting my computer or switching to other computers does not alter the problem.

best regards

Fabian

[RichardTanSY_Altera]

Thank you for the test case. I’ll try to reproduce it on my side.

Moving forward, if anything, all communication will be conducted via email due to the upcoming FPGA Forum transition.

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Please be informed that starting October 1st, the FPGA Forum on community.intel.com will be placed in read-only mode.

You will still be able to view and access existing content, but new posts, comments, or edits will no longer be permitted during this transition period.

For urgent technical support, we kindly ask that you reach out through Intel Premier Support (IPS) via your DFAE (Altera authorised distributors) engagement.

We appreciate your patience as we prepare for the official launch of the new FPGA forum on October 14th, where posting capabilities will resume.

Thank you for your continued support and understanding.

Regards,

Richard Tan