My SD is a little lower than yours, and fully buffed I don't have a problem with 1k+ TPS. Since Gorefiend allows for exorcism, your TPS should be higher.
First question -- what are you using to check your TPS? If it's Omen, the default settings for that program don't provide accurate TPS data, because the value updates too quickly. So, if that's the case, you may be doing better than you think.
If you're sure 800 is your TPS, then pay attention to managing your CDs, always do a full rotation, use SoR as your seal, max rank consecrate, etc. You should also regear to use the libram of divine purpose. The BR libram is useless unless you're dying for uncrushable. If that's --the-only-way-- you can get uncrushable, then keep it on. But that's probably not the case for you.
Some other suggestions, since you say your DPS is holding back. You have a good amount of spell damage, but you've passed up on a few equivalent pieces that do have spell damage. Jungle stompers, for one, are essentially the equivalent of the 2.3 badge boots, except they don't have SD. So, you might pick up those for 60 badges. T4-T5 aren't amazing, but neither are your badge gloves. I'm sure you're waiting for a token drop, because T6 gloves are great. Also, why not get the S2 shield with SD on it?
Make sure to maximize your threat at the start to get a lead, too. Minmax your wings, don't judge wisdom during it, get a MD, put up crusader if needed...
Also, obligatory "DPS is always going to hold back no matter what you do blah blah" (true to an extent, probably true in this case).
_________________
