Monitor Upgrade -> Framerate Lag

So I recently replaced my 21" CRT (running at 1280x1024) with a pair of 21.5" LCD screens (running at 1920x1080). I'm using a GeForce GTX460 video card, and left the video settings unchanged after the upgrade. (if necessary, I can add a full listing of what's set where, but for the issue I'm having it doesn't seem to matter). I run the game in a window (and solutions that involve 'don't run in a window' won't work for me, for a variety of reasons).

Since this upgrade, whenever I look at a group of players (Wentworth's, Pocket D, Trials, etc) I suddenly begin suffering massive framerate lag; I drop from '40-45 FPS' to '1-5 FPS'. I thought that this had something to do with the character textures, so I lowered the Character Texture Detail from High to Medium and applied the changes. This solved the problem immediately... until I hit a load screen.

Once I was in the new zone, the problem reoccurred immediately. Once again I opened the graphics settings, and changed the Character Texture Detail - this time from Medium to High - and applied the changes. Again, this immediately solved the problem. I've discovered that applying ANY graphics change - no matter what, so long as it causes a load screen - solves the problem until I move to a new zone.

I'm baffled. The problem is not 'my settings are too high'; it doesn't matter where the settings are, I get lag when viewing groups of people until I change the settings, and apply the changes. I've also discovered that it definitely has something to do with the resolution I'm playing the game at; hooking up the old CRT monitor and using it at 1600x1200 resolution caused the same problem as playing with the new LCD at 1920x1080. This issue does not happen with the CRT set at 1280x1024.

In addition to the above troubleshooting, I have tried updating the graphics driver; when that had no effect, I tried tearing out the graphics driver by the roots and reinstalling it with the newest one, and that didn't help.

Has anyone seen this behavior before, or can anyone suggest a solution that I haven't already tried? The workaround described above makes the game playable, but it certainly isn't fun to keep doing it.

[EDIT]

On a friend's advice, I tried /unload_gfx instead of changing graphics settings. This ALSO fixed the problem, but it remains temporary. Creating a macro button to do this is not too inconvenient, but still isn't something I should need to do. Ideas on a permanent solution are welcome.

I don't have advice to permanently fix it, but for a quicker workaround, try /bind f12 reloadgfx and hit F12 each time you lag -- it should reload the graphics, which would give you your regular framerate back.

You went from a 1.25 MegaPixel to a pair of 2 MegaPixel monitors. Possibly the scaling up of all the multiple frame and Z-buffers has eaten away too much of the video memory and now there isn't enough left to manage properly for immediate textures. The changing character texture level or flushing of the texture memory is, for a short time, allow the game to use the remaining memory more efficiently.

Also I half remember a problem with nVidia and driving two montors with acceleration turned on for both of them, but I'm fuzzy on that.

Just saying Z-buffer takes memory as well as frame.

If you're running Windows 7 (or Vista), the OS uses the 3D hardware for the fancy desktop visuals - this may be sucking up more memory than you have available by the time the game is running too.

If so, Disabling the aero theme may help - try Windows 7 basic. That should reduce the video memory the desktop uses.

Something else to check is to see what resolution the game is running in - there's the 3d scaling setting, which renders the game smaller then scales it up. That will lower the game's use, as will lowering or turning off antialiasing.

Good luck...