Thank you for the post.
I am not experiencing any FileMaker Server 13 Admin Console slowness related to version 3 update.
A few additional questions to assist us with narrowing this down:
1. What is the FileMaker Server 13 computer's operating system?
2. What system resources (RAM, HD space, processor) are dedicated to the FileMaker Server?
3. What version(s) of Java is installed?
4. What (if any) other programs besides FileMaker Server 13 are installed?
5. Is this computer a dedicated FileMaker Server free of other third party applications?
For best performance, FileMaker Server should be run on a dedicated machine reserved for use as a FileMaker server.
Lastly, if this computer is a dedicated machine, meets the hardware and operating system requirements, and is free of third party software that could cause conflicts, please let me know and I will provide instructions to submit the system information file and logs for review.