I have noticed that my TWS always gets slow at the end of the day. IB told me that I could increase memory usage by doing the following: https://www.interactivebrokers.com/...guidebook/priceriskanalytics/custommemory.htm I have increased the memory to 1200 MB and I still have issues. My computer has 32 GB of memory so there is no issue on my system. You can monitor your memory usage by clicking Help - About Trader Workstation. When I do this I notice that my usage constantly goes up during the day. Every time I bring up an option chain - the heap memory goes up. But when I close the option chain - the memory doesn't go back down. Is this a memory leak? or is this what should happen? The other solution IB offered was to use the 64 bit version but I can't because I use DDE links and this won't work with the 64 bit version. I could also shut down my TWS and bring it back up but then my DDE links will break. Has anyone else experienced these memory issues? Any idea if there is a way to clear memory cache without shutting down TWS?