L4d2 bogging down on me

just bought an nvidia 460 when my 7900gs burned out on me. When a horde comes it can drop my fps to the teens. Is this reasonable? I can post my full list of hardware when i get back to my computer.

Hardware list(running XP):

* Galaxy 60XMH6HS3HMW GeForce GTX 460 (Fermi) GC 768MB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
* AMD Athlon 64 X2 4200+ Windsor 2.2GHz Socket AM2 89W Dual-Core Processor ADA4200CUBOX
* ABIT KN9 AM2 NVIDIA nForce4 Ultra ATX AMD Motherboard
* G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-2GBNQ

I had frame-rate problems in general before this new card. The story is I blew my 7900GS, knew nothing about the newer nvidia cards and bought a 9800 (i was thinking it was the old numbering system which made sense to me and figured it would be better than my 7900). The 9800 clearly wasn't cutting it and just gave me poor performance with regular l4d so I knew i needed to upgrade. Then I got the 460.

I never played l4d2 with anything but the 460 as it's a new game. The 9800 was struggling in general (not horde only) just because it was a lower end card.

Thanks for the driver advice, I'll give it a go. Fragmentation shouldn't be a problem, I've got an SSD.

Could be the cpu, you have other programs running that could be interfering?

I have a friends playing l4d2 on a 9800 and a 460 and they don't have any issues. I am playing it on 7800 GT and have no issues.
However, your CPU is on the low end and my guess is that is your problem.

my specs are:
AMD 9950 X4 @2.6
4 gig DDR2
7800 GT

Wow what a great amount of responses! Thanks everyone.

Yes I agree 2G may be cutting it close but keep in mind it's XP not a <insert bloaty-ness here>, but I try to resist the "hardware is cheap, throw the biggest angriest thing you've got at it" mentality that is becoming so popular these days. I will try throwing another G or two borrowed from my wife's computer to see if it makes a difference.

I've tried reinstalling (uninstalling first) the video card driver, and installing DX9.0c as per the request of the card when installed. I have some spare parts around I can play with.

Olin, I will try turning off multicore in the game, thank you for the suggestion.

I also agree with attempting to overclock the cpu. It will be my fist overclocking experience but I'm sure I can handle it. If it burns up it might just be time for a new build altogether as it's about 4 years old.

jgiron, you also state that you have friends playing on much lower end cards than I currently have. Do you know if they are playing max settings or not? I haven't specified but I *am* going for max settings.

I'll replace hardware before I give into a DX9 game being too much for me.

Thanks again all.

Run a tool and see if your CPU or GPU is maxed out while you're playing and a horde comes. I played lots of games with 2GB before moving to 4GB and didn't notice a huge impact

I am the one with the low end card and I play at medium setttings, my firends have a high end card 9800 GTX and 560 GTX and play at high settings, they also have higher end cpus (core 2 duo @ 3ghz and a core i5 at 3ghz)

Ok so the list of things I have tried is as follows:

Software:
Turning off multicore
Uninstalling and reinstalling card driver
Monitoring CPU usage (never went over 70% even during a horde)

Hardware:
Tried adding more RAM
Tried using a more powerful PSU

I just noticed that I missed a suggestion of watching to make sure my GPU isn't maxed out, so I will try that.

Other than that all I have left is OC'ing the cpu, but if I'm only at 70% during hordes doesn't that mean it's likely not a CPU issue?

I verified that my wife's computer doesn't bog down like mine. However she thought she was at full settings and wasn't. For anyone else trying to replicate what I'm seeing make sure you've got filtering and AA cranked all the way up and turn the film grain amount completely down.

Do you guys still think it's worth attempting an OC of the CPU?

The only thing that I've noticed now after rebooting a couple times (and I forgot this happened earlier) is that after installing that new video card, I get the windows hardware installation box that pops up each time i reboot and when i click cancel to find suitable drivers it says that it failed to install UAA audio something or other.

At first I dismissed it because it was audio but now i realized that this is a new box popping up and has only happened after I installed the card. I have no sound card, it's integrated so I'm not sure wtf the deal is with that.

Thoughts?

Edit: What about the fact that I'm running a PCIe2.0 card in a PCIe slot? I know they're backwards compatible but is it possible the bus attached to this slot can't handle what the card is trying to pump through it? If this question didn't already put it out there, I don't know a whole lot about mobo's and FSB or if there are other buses, etc