I have an amd FX-55 processor (a bit better than the 4000+, i think) and a geforce 6800 ultra video card. Would upgrading to the best agp card on the market, the 3850 512mb cause insane bottle necks (hence: not a good purchase) or will it escort me into the golden age of Crysis and what have you? Any good insights are appraciated.
 
Normally I wouldn't consider something that competes with a geforce 8 series on an old cpu, but it was the best cpu at the time of purchase, right before they became stagnant, forcing the era of dual cores, and games do usually bottleneck the GPU way before they touch the CPU. At least thats what my minimal knowledge tells me.
 
FYI, the system runs off 2 GB or ram.

More likely then not, yes it will bottleneck that HD 3850 to an extent, maybe one that isnt noticable if you set the graphics to High to take off the load from the CPU to the GPU.
 
However it would just be in your best interest to buy a brand new system when you can no use buying a HD 3850 for a dead bus(Nvidia doesnt support AGP any more with its 8 series)

I have an FX-55 rig with 2GB of mem and ran 4 different cards through it's life as my main gamer.  The last was an 8800GTS 320MB, about the power of the HD3850.  I saw gains with each GPU upgrade.  But from the first card, a 7800GT to the 8800GTS, the difference would be HUGE.  I think that CPU is fine to justify and HD3850.  Sure you will be more cpu limited in some games (Supreme Commander) and in many games a faster cpu would allow for better performance with that card.  But in other games you will still be more often GPU limited.  If you play at 1280x1024 or above, and would like to keep using that rig, go for it.  
 
BTW, The system did play Crysis ok at 16x10 mix of med with some high settings and no fsaa.   It stuggled like everything does, but at 16x10 res I think the 320MB GTS was hurting me more than the FX-55.  Look at reviews and the 320MB 8800GTS struggles at crysis above 12x10.  

That's exactly what I wanted to hear. A $200 dollar upgrade to bring a dead pc back to life. Thank you guys, and thank you 3850. I'm gonna play crysis!

It may be what you wanted to hear, but I dont think its accurate.
I would say your definately going to be bottlenecked with a single core cpu.  Since Crysis isnt going to play very well on a 3850 anyways, let alone a bottlenecked one, I think the $200 would be better spent on a complete system upgrade.

You show me a 200 dollar gaming pc and I'll consider it. Anywho, I already ordered the card. If you're curious to see what happened, let me know, and I'll get back to you in two days.
Hell, I'll post anyway and let you know who was right.

 
Did i read somewhere that ATi didnt support the 3850 AGP driver wise (or yet, atleast)?
 
Be carefull how much you spend on dead end hardware...

You will see massive gains from a 6800U to that HD3850.  And crysis will be way more playable with that new card even with the FX-55; been there done that.  Through the first few levels, the cut scenes were the worst framerates I saw.  
 
Anyway, if you like I'll run some crysis benchmarks on that rig for ya. I think you should do it yourself too.  If you don't have the game yet, play the demo while you wait for your card.  Then run the built in GPU benchmark at a few resolutions & detail levels and record your results.  Do the same with the new card. there may not be a difference at 800x600 medium or 1024x768 low.  But there sure will be at 1280x1024 medium or above.  The HD3850 will surely allow for better playable settings (higher resolution and/or details) compared to that 6800U with the same CPU.  Crysis is better on dual core for sure, but it also crushes the GPU.  Min spec is a P4 2.8 or Athlon 2800+, you CPU is twice that level.  Min spec Nvidia GPU is a 6800GT, just a little below your Ultra.

Obviously the better CPU you have the more performance you will see in games and the video card will follow suit. But I don't think your setup will "bottlelneck" with a 3850 card. You will be very happy with the upgrade. Have you considered the 9600GT as well? it's in the same price range and seems to perform a bit better on more games.  However if the games you play seem to favor the 3850 I'd stick with that.  Just throwing the option out there. Always good to have options.

Geforce was never an option, Jay. It's an AGP mobo, and Nvidia stopped suporting those a while back. I doubt there will ever be another AGP video card.
 
About the drivers, I had heard the same thing. Looks like I'll be either stuck with the drivers on the CD (never thought I'd use a cd to install drivers again) or go with third party. At least until ATI gets their blank together.

Ohhhhh AGP. gotcha.  geez that would bottleneck your card more than a CPU would.  But it would still be a decent card if that is all you are looking for.

I'd like to see the HD3850 tested  in it's AGP form vs PCI-e form.  I don't expect much difference if any.  There was none between the X1950 pro's, but this is a step up so who knows. Would there be a difference at playable settings or only so cranked neither is playabel anyway.  

I don't think AGP would bottleneck anything. It's more competent than the Mobo/GC manufacturers would have you believe. The CPU has been my only concern.
 
In lighter news, newegg shipped my order two hours after I put in for it. I should be receiving it any moment. If only I didn't have to work till 2 am.