Slow DDE Writes to ControlLogix via RSLinx

We are experiencing random slow performance when writing to a string tag in a Clx PLC via ethernet and RSLinx 2.43. The write is most of the time fast (100ms or less) but after 5 writes or so, it would take more than a second to do the write. Basically, we are writing a "0" to the string which the PLC has set to some value containing 15 characters. This is a Wonderware Intouch application using RSLinx DDE to talk to the Clx. Is there a way to get more reliable and consistence writes to the PLC?
Thanks for any help.

Get rid of DDE if you can, and use suitelink. It's a lot faster and more stable. You need to set up an OPC link. Then in Wonderware, under the configure topics tab, you would put something like this;
Node Name 169.265.109.91 (CLX ethernet address)
Application Name Linx
One of our Wonderware apps where I work is still using DDE. P.O.S...slow and unreliable. Another day, another project.

For a possible short term fix, maximize your paging file size for virtual memory. DDE is asynchronous so alot of things can slow it down (antivirus programs, etc) Also, a perdiodic scan with a registry cleaner can help too. I've been using Registry Mechanic with good results.