I think with grub2 it is bad practice to edit grub.cfg directly
I added those switches to /etc/default/grub
I changed the line
And then ran
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.i915_enable_rc6=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1 pcie_aspm=force"
Edit: Out of curiosity: which fstab switches are you using? It is my first time using an SSD and the only two that I have found that seemed to be of use were noatime and discard. Is there another switch that I should be aware of?