With those specs it should run better. I have phenom x4 2.4 ghz, radeon 6850 and it's fine but I played witcher on nvidia 9800GT in past and even then I could max almost everything and it was still playable.
Today witcher started to slow down but I realised that I accidentally had pressed button that starts recording the stuff what's on the screen. =)

No malware at all,
I run Malwarebytes 3x a week also keep my firewall and anti-virus fully updated and do AV scans twice a week. Yeah, I'm paranoid. btw other games run ok, no problem

A 4670 is much weaker than a 9800GT.

A 4670 is equavilent to a 9600GT, from memory.

Yes, he should be getting better frame-rates, but with the OP's card, I wouldn't expect it to be playable.

His card isn't powerful enough, especailly when you look at this game's draw-distance.

Everything is rendered on the screen, regardless of distance.

The performance he's getting is much worse than I have gotten with a much worse card. That's what concerns me. I can get better fps out of a Pentium D with a 7800 GS.

So there's something much worse at work here than any deficiency in his graphics card.

I'm new with ati cards but OP's card didn'tsound so bad. =) 9800GT is pretty old card but it truly was a good card, I still own it, if this radeon explodes. And the drawing distance indeed makes a great impact. But game loses many aspects if it isn't full.
I mean I have played crysis 1 and tried two but first one seemed that it looked better. So, still I look witcher and think "damn this looks good" =P

Maybe it's the art style.

I saw another thread where someone had similar low FPS issues, and they solved them by opening their Catalyst Control Center for their ATI card and resetting everything to the factory settings. Maybe this would work here too? Check it out:

http://www.gog.com/en/forum/the_witcher/unnecessary_slowdown