I'm a returner to ARMA after a long while away, and was really p...ed to find the SLI flickering problem.
BUT after following some guidance  (I think from this forum) I installed nHancer with the 181.22 drivers and used the Crysis.exe to run ARMA.exe.
Eh Voila Perfect. Anywhere between 40 -80 fps (in FRAPS) 1920 X 1200 Everthing on max.
Looking good.