Julie,
I would need to know more information about your environment.
1. What is the size of the locator? What type of locator is it (Created with Create Address Locator Tool or Create Locator tool)? Is it a composite with many locators in it?
2. What client are you using to geocode? Pro, ArcMap, etc...
2b. What version is the client?
3. Where does the locator exist? Is it hosted on a Server (if so, what version), local on the machine, is it on an SSD or HDD?
4. What is the machine configuration? Memory, #CPUs, #cores per CPU, disk types SSD or HDD.
5. Where are you reading the table from (FDGB, Enterprise GDB, other) and where are you writing the results to?
6. How is the locator configured? Is it configured to use multiple threads?
I may have more questions after you answer but there are many variables that could cause a performance problem but typically the answer to your problem will not be that you have to split the table into smaller chunks.
Brad