If some universities do not require GRE, will having GRE make me stand out compared to other applicants in USA for a Master's?

Yes, submitting a strong GRE score can help you stand out, even if the GRE is optional for Computer Science master's programs in the USA.

A high GRE score may strengthen your application, especially if other parts of your profile - such as GPA or research experience - are less competitive. However, some universities focus more on your academic record, research, and personal statements than on GRE scores.

Overall, a strong GRE score can be an advantage, but its impact varies by program. Make sure to also focus on your statement of purpose, letters of recommendation, and relevant experience.