Yo, folk, help me out with this issue, please.

So, I bought a new GPU - R7 250X and now to my surprise the performance in game is worse than before on 8800gt. It's even worse than that from my early 2007 years, when i had an old athlon/ati9600pro system.

What's happening is that the environment/world movement and shakes/camera movement doesn't feel smooth or 60 fps.
It feels sluggish and slow motion (at like 90% full speed). I haven't been around much in the last couple of years, but i don't remember game ever running this bad for me, not even back in 2006/7.

The sluggish,stuttery feel is especially noticeable at SC and when turning left-right or when coming around a corner and when objects come into view. There's also screen tearing apparent.
I have it VSynced and get constant 60/75 fps, depending on the refresh i choose (i'm testing a 1440x900/75hz monitor ).

Anyone got a clue what's going on here ? Or is this just the way the game is and i've forgotten while playing more modern sims...

pc:
g1610
4gb ram
r7 250x
win7
1440x900 monitor

Thanks,
Jan

Some people have reported that their GFX card would go into power saving mode for some reason, which would result in apparently bad performance.
Putting their car on max performance fixes the issue. Though it would be interesting for us to figure out why these cards think they can save power in the first place, when in fact it's being used. We haven't figured that out yet.
So have a look at your card's control panel and see if there is a power saving mode that you can switch off.

Thanks; Victor, for the swift reply.

Were would this option be in catalyst ? I can't find it.

Btw, from what i see in Afterburner, the card is functioning normally. I doubt it's in power saving mode. The readings show roughly the same values as in other games i play. Gpu core/mem clock is at full, only memory usage is at 300(of 1000 available). And fps shows stable 60/75 fps.

No idea I'm afraid. It could even be there's not even a power saving feature on your card. I couldn't find any such option on my nvidia control panel either.
But there is a PCI power saving option in your regular Windows' power profile that you could check. You should be able to find it in the advanced power options edit window.
Though again, no idea if that'll fix anything. Your issue could be something completely unrelated.

Oh, that brings me to the silly usual question - have you checked that you have the latest drivers? Rather than perhaps any drivers supplied with the new card itself.

Your CPU (if that's a Celeron G1610) is quite weak.
On the other hand, if it's enough for LFS, it has a built-in GPU (Intel HD Graphics). It may be that every application uses this GPU as the primary GPU. You can set this in Catalyst, so that LFS uses your dedicated high-performance GPU (R7 250X). Also, make sure that everything on your computer is set on high performance.
More info on switchable graphics:
https://support.serato.com/hc/en-us/articles/202305784-Changing-graphics-card-settings-to-use-your-dedicated-GPU-on-a-Windows-computer-

Yeah, it's a very budget system, but i used to play LFS smoothly almost 10 years ago on an Athlon/9600pro configuration if i remember correctly ...So i believe it's safe to rule out the (lack of)power of the system here.

I have the latest drivers, yes. I've set in the catalyst to override the application with AA and AF now and i've chosen the high performance plan in windows. It seems a bit smoother overall now, but coming around the corners and turning still makes the world movement feel sluggish. It's normally playable, though, so it's good enough to check out the game again after a long time.

Anyway, I just wanted to check out the new Westhill. The track is ok, but what i especially like is driving on all the side roads and how everything is interconnected and accessible. Pretty impressive and it still looks good enough, coupled with decent sounds and physics to provide a quality sim racing experience imo.

My guess would be this, slow processor, minimal ram. Your old card didn't use system ram, only it's own so 4 gig was available for your system.
Your new card uses some system ram for video magic. This means less system ram, less performance with LFS.

Try throwing more ram at the system, up to 8 gig and that may help, run ccleaner, stop all unnecessary processes/start up programs, (msconfig)

Then, if money is an issue, try running an old 775 board with the fastest core 2 duo/xeon processor you can find.

LFS is only single core so the fastest's OC processor you can run helps far more than a flash video card.

Pretty much the opposite to most other games.

No way it's ram, man. I told you i used to play this game smooth on a 10 very low grade athlon system in the old days.

I checked ram and LFS.exe is taking 200MB, lol. Really weird thing...
I don't get it.

Fps look fine and stable all the time (75 at 75hz), but once i start driving everything is so sluggish, the world moves past me in such an oddly slowed-down manner as if it was 30 fps or smth. The camera shaking from the bumps and other forces is also very abrupt and not smooth at all, although again no sign of fps drops on the fps counter.

Victor says ''your issue could be something completely unrelated''.
What sort of ''completely unrelated'' thing could be causing this ?

Ram problems, disk problems maybe ? Anything else ?

Quote from Racer X NZ :

My guess would be this, slow processor, minimal ram. Your old card didn't use system ram, only it's own so 4 gig was available for your system.
Your new card uses some system ram for video magic. This means less system ram, less performance with LFS.

What are you on about... discrete desktop graphics cards that use system RAM haven't existed in the last 10 years.