Does the choppy connection occur on wired or wireless? Or both? Changing wireless channels might help resolved this. You can also adjust the MTU size. Try checking out these links:
Top causes of dropping wireless connection on a Linksys router
Resolving dropping wireless connections
Determining and setting up the correct MTU size
This router has an Auto update feature. If you have not enabled it, you may download the up to date firmware from this link: http://support.linksys.com/en-us/support/routers/EA6500