Dear Jia,
1. for basic ideas on reducing the memory requirements of your analysis, please see ATENA Troubleshooting, 2.4.1 Out of memory error during ATENA analysis and 2.2.17 The analysis runs too long. How can I speed it up? The document (PDF) is included in ATENA installation and also available for download from our web (Products - ATENA - Documentation).
2. A portable (USB, eSATA) SSD can be used as additional disk space, not working memory (RAM).
3. Have you looked into the Output files (.out, .msg, .err) in the AtenaCalculatio subdirectory of your GiD model directory? Maybe you can find some error or warning message there...
4. A similar problem can occur if there is a blocked ATENA-related executable in your memory, for example, the automatically started ATENA Update Check utility, deadlocked due to communicaton problems. Reboot the computer, run ATENA Update Check manually, click OK or Cancel in the UCh dialog, and then try again to start the analysis.
Regards.