I'm afraid I'm having the same issues... running a Nvida GTX 280. Nice no problem in space, as soon as I hit the ground, or board the space station it's like I've been dropped knee deep in mud!
Coming from LoTRO that I can play pretty much maxed everything with DX10 gfx which IMHO are not really anyway inferior to ST:O's renderings (just different) the drop in performance is staggering when you compare these MMO's side by side. Dropping graphics setting has a little, but not a major impact.. and I am running the 190.62 drivers.
I just hope they get this issue resolved... it (amongst a few other things) has unfortunately coloured my judgement somewhat with respect to pre-ordering/lifetime subs!
I'm on a Macbook Pro that has a Geforce 9600GT, running WIndows 7 Pro 64bit. With the stock Apple drivers its running slightly slower, but still quite fast and playable on the ground.... maybe if we can find like 50 people who doesn't have a problem, along with 50 who do.. and get full system specs and software/driver versions, we can find a common link.