Fs9 frustration

Hi all right where to start

I run fs9 as part of my home cockpit it seems every time I have it running right and add some new toys to it something goes wrong :-)

Just recently fs9 has been running great I use the wilco 737 and run 2 LCD and 3 CRT monitors as part of my set up, 2 outside views and 3 as the mip running the gauges behind the mip panel, I was recently lucky enough to have purchased a real 737-300 throttle to convert to sim use and this is where the add new toys and something goes wrong comes in, two of the CRT monitors blowed which wasn't the end off the world so I replaced them with 3 LCD ones to run the gauges behind the mip, since then I have hit all sorts of problems, the sim ran great with its old monitors I have 1 PC which feeds all monitors using display link adapters I have numerous add on sceneries all maxed out and had a stable 25 fps locked which is all I need and was quite happy with. Now with the new monitors it get a fluctuation in fps from 25 down to 8 ? I have searched the flight sim community and not much has come up on LCD monitors affecting fps, I haven't used the sim for 3 months so I don't think any software changes have taken place but something is definitely happening in the back ground Example is sitting at the gate in the default cessna on one screen and all other monitors turned off the fps is around 20 that's at Latin vfr cayman mwcr now before the swop over I could sit in the 737 at the gate with 25 fps locked and it not drop from gate to gate. Any idea's of where I should start looking?

Thanks in advance