yes because essentially what SSAA does is take multiple rendering samples per pixel so for example with 2x SSAA, you'd take 2^2 samples for every pixel (representing 2 samples in both axes), so every displayed pixel will be an average of 4 sampled subpixels
it also means that it'll (in its most basic form, that is - MSAA is an optimized implementation of SSAA, described above) actually be rendering 2^2 the amount of pixels which obviously very expensive (and then you get to 4x, which is 4^2 = 16 samples and 8x is 8^2 = 64 and whoa!!! suddenly you're rendering your depth and stencil buffers at 15360x8640 instead of 1920x1080)
on the other hand, postprocess AA like FXAA / SMAA aren't really AA, it's a bunch of clever assumptions to smoothen / blur out detected edges after the initial rendering process (hence the term post-process). It's very fast because it's a rather efficient calculation done after the rendering process, so at most the amount of processed pixels is equal to your native resolution (so for a rendering resolution of 1920x1080, it'll always be 1920x1080 - it's actually impossible to change this because.... you've rendered your scene already). The only bad part is that it's never going to be true AA - it only seeks to imitate its end result........ It gets very close, though (especially for its great performance gains!):
FXAA and SMAA are two postprocess AA techniques, MSAA is, well.... MSAA.