32x anti aliasing is way too much .. so the performance hit is excepted.. in case you are willing to use FSX in DX10 mode you will need Nvidia inspector software along with steve DX10 fixer.. and there is a guide for how to use DX10 in FSX
Google
.. get the guide from the first website in the search page
follow the guide carefully because if you don't set up DX10 in the right way it won't work.. I recommend 4x anti aliasing in the fixer and 4x sgss in nvidia inspector(suitable for ur specs).. sorry for writing in English. no Arabic keyboard available for the time being