No dsx10 = low fps

I just joined the avsim community and I really don't have the time to really find out which forum this belongs in. 

Basically when i have direct x 10 preview enabled with max settings I get perfect fps always above 60. Only problem with this is mod planes skins and textures don't load as they're not compatible I hear. when I disable direct x 10 I get horrible fps in 15-20s. I turn it down to low  with billinear and it's still mediocre at 30 fps. 

Specs: 

4gb corsair vengenance ram

intel i3 3220 ivy bridge  2 core

gtx 650 ti 1gb ram 

I hear having a dual core cpu is much better than a i7 as it is more configured for fsx. 

I'm assuming my gpu is newer and made to run with dx10 

Anyways I'm a noob at this and need a few guidlines

Thanks