I have the same issues. I only have a GeForce GT 220 which I realize is an older card, however, I can have the exact same settings anywhere else in the game and have no problems whatsoever. Also, I've attempted turning every On/Off option to Off and all High/Low settings to Low and still seem to be getting this lag.
Last time I did Khitomer, it was fine (even with normal settings), and right now (as I post), I'm back at Khitomer, and the lags back. And I turned the settings down to bare minimum, and still getting it.
Like said above, it has to do with the gates. Because sometimes it works fine, and then it doesn't.
Please, look into this Cryptic.
People hate Khitomer, plenty because of the mobs. The video lag is only compounding the issue.
It's the beginning of Khitomer Accord, first space part - all in my fleet that tried KA (with various Graphic Cards) also had this issue; I also saw big slowdowns on this, even with my Radeon 5850.
Not sure, either view distance is to far, or the warp gateway in the middle of the "map" is producing to many light effects at once.
I've had this problem as well. The first time I played Khitomer it was a slide show when I first started to attack any of the Borg. After being destoroyed, I turned off dynamic lighting in options and haven't had a problem since. I'm using GeForce 260 with no problems at all on any other map in STO. Maybe that might help you out if you try it.
Yah it seems to happen half the time in the first stage of KA, right when you get close to the time gate. Exiting STO and relaunching the game while your teammates wait fixes it, but it's pretty annoying.
One other pet peeve about the opening stage in KA. There used to be turrets surround each gate, they were removed for good reasons. However their physics still seem to be there, albeit invisible. How do I know this? Well I fly into them all the time, and it can be quite annoying! :p