Ok guys, I have just installed my new ENGTX260 and been doing some tests with nHancer settings as per famous nick's post.The thing is that, although it looks a bit better because of antialiasing, the frames droped compared to what I could see with the ATI 5700GPU-Z shows better numbers for 5770 (shaders clock... etc)but in furmark benchmarks the GTX260 outperforms the 5770I'm totally confused

If you simply removed one card and installed the other there's a good chance that some remnants of the old card's configuration remain. Try deleting your msfs config file and see if that makes a difference. You will of course have to redo your graphics settings afterward. Also you should clean your old driver installation(s). Uninstall software from both ATi and Nvidia and then reinstall the latest driver from NV.

Something was messed up in my system. Decided to reinstall FSX and all my addons eventually and it's all good now. Thanks for the tips everyone :)

Sorry for hi-jacking your thread here dazz, but I must ask since I'm into buying either a 5770 or a GTX260 for FSX only:Was there a big difference between the two? I'm going to run a three-screen span view, so I guess it's quite important to pick the right GFX, even though it's the CPU that get's most of the load.Thanks!

I kept the GTX260 as it can run better AA settings, but there's not much difference between those two. In the beginning the 5770 was awfull, no AF, no vSync... then the latest drivers and *******' tweaks solved that.Never did 3 monitors so can't really advise there, I'm sorry. Maybe WideFS to run the extra views if you have a spare computer?