Hello Engineer,
I'm not an AOL fan and don't use it; however the ispeedprogramme does have an "ISP Specific" folder for a number of ISP's and when I selected AOL the following settings appeared as default,
MTU 576
MSS 536
RWIN 3216 (produced by a multiplier of 6)
I can only assume this has been a tried and tested set of numbers the makers of ispeed have found to work best.
Hope that helps.