That slow framerate in FSC

Not a suggestion or a bug report, just a general whiiiiiine.
Friend invited me down today, and since I got the elevator pass I figured why not. I'm still not fully geared up for it, but I got a miracle set, wise owlite, voltedge, DTB, Gigawatt and a Plasma cap. Not great, but not bad, right? But the biggest thing that killed me was the framerate. I can't do combos, I can't shield cancel, hell I can barely shield at all because I get 5-10 FPS down there.
Why, OOO? WHYYYYY? Is it really that hard to optimize these levels a bit better? I mean, I'm glad you're making some progress with the GC freezes so that I only have to deal with a constant low framerate rather than a low framerate combined with 2-3 second freezes, but still. Put some of that Sega money to good use and fix this!
My team was kind enough to drag my charred corpse through the levels and boss fight, where I discovered interesting tidbits like "the wise owlite shield can tank a mace hit, but not if it pushes me into shadow fire" and "if I get stunned when I'm on fire, I'm probably not going to make it to the fountains to extinguish myself". These things will likely be good to know some day if I ever get a decent framerate so I can properly put them to use.
It was my third time down there and the first time doing the boss fight. I'm at least glad I went, but overall I'm disappointed. It's just unplayable when the whole game turns into a slideshow for the entire stratum, and this is coming from a player who just finished up grinding RT for a full quicksilver set: I like to think I have a very high tolerance for low framerates.
Also I got a heart on the prize wheel going down to the core, not to mention a vitapod in one of the prize boxes. Thanks, really made the trip worthwhile.
The sad thing is I'm really not sure what to do in the game now. I'd planned on grinding FSC some, maybe do a video run or two, once I got done with heating up my quicksilver set in RJP (almost done). I can't do that with this BS framerate though, so what does that leave me? Mess around in random T3 levels? Whoop de do, gun puppies shoot 5 bullets instead of three, I've done this all before in T2. I'm sure as hell not going to run shadow lairs.
I'm not regretting buying the elevator ticket, I'm just wishing I had some playable content so I could put it to good use. OOO, I am disappoint.

Yes, constant slow framerate is usually graphics/CPU, not network or server response related.
I had a half-decent PC up until yesterday that I bought back in 2008, and today I'm upgraded to a more current, but still not top-of the line gaming one. This made possible the jump from low graphics to full without problem. I still have to check on Ironclaw lagfest though.

FSC can really be unplayable sometimes. There was a time my whole party got so sick of this we all returned to Haven after D25.

I 'fixed' the lag by playing with low graph options. Looks fugly but no more lag.

Plus these words into forum search and a new world awaits you.

Yes, I'm quite sure it's graphics/cpu related and not network lag. My net connection is thankfully pretty solid.
For reference, I've got an A-X2 5200+ and an ATI 4870, 4 gigs of RAM of which a gig is carved out for SK. This is not a world-beating system in this day and age, but it's more than fast enough for every other game I play.
Does L4D2 slow down when I have hundreds of zombies swarming me? Nope.
Does Portal 2 slow down when I'm warping through gigantic, highly detailed levels? Nope.
Does Torchlight slow down when I'm up to my eyeballs in spiders and skeletons? Nope.
Does Spiral Knights slow down when I'm plumbing the depths of the clockworks? Not unless I'm in IMF, FSC, and occasionally in lockdown.
I think it's an especially damning comparison in the case of torchlight, which is a similar third person clicky dungeon crawler: It manages to put more on screen with more sophisticated visual effects and ambiance without even a trace of the performance problems that plague SK. (My only performance complaint with torchlight is that it takes a mysteriously long time to load new levels)
And yes, I've read the performance tweaking threads. The tweaks they advise are generally aimed at preventing the periodic freezes caused by GC thrashing, which isn't the problem here.
I can understand if IMF has some slowdowns. It's relatively new content with new game elements, and sometimes it just takes time to profile and optimize these things. However, FSC is, what, the oldest boss content in the game? (I dunno, was RJP earlier?) It's really inexcusable that it's been this long and still performs this badly.

T3 isnt just t2 with different puppies though... go find yourself a stratum 6 flame or fiend arena.
Maybe it's your computer?