How much memory is being used by the Log Reader LiteSpeed process?
LogReader works on the LiteSpeed Console side (the server side component is just sending DBCC LOG records from server to read online log).
It uses max 640 Mbytes of physical memory. If it not enough it uses the temporary folder for storing pages.
The Log Reader runs from a separate process (LiteSpeed.exe). Lowering SQL Servers memory will give the Log Readers process (LiteSpeed.exe) more memory to process the log. By seeing how much LiteSpeed.exe grows, the amount to lower SQL Servers memory can be extrapolated.