Thread: Random lag spikes in L4D2 on PC

So like many others, I'm experiencing a problem where every 5-10 minutes or so, my framerate drops really low for a period of about 6-12 seconds, after which the game begins running smoothly again. During that short period where my framerate drops, any sounds that are playing will stop mid-sound and go on an endless loop. (so I'll repeatedly hear a part of a gunshot, or "Louis!" might become "Lou- Lou- Lou-").

As far as I can tell, it has nothing to do with what's happening ingame, since I've had it happen both with large mobs of zombies on-screen, and when killing off a couple straggler zombies in a mostly empty area. I'm not really sure if it might be a latency issue. Things supporting it being a latency issue would be that I haven't noticed any framerate drops in offline mode, and I have noticed my latency going high (around 300-500) during a couple of the frame rate drops. Reasons I'm not so sure is that my connection doesn't seem to have any problems with the other online games I play, and oftentimes, my latency seems to be low (around 10-50) as the framerate drop occurs.

While my computer is decently old, I'm pretty sure it's not my hardware, since my system meets all the minimum requirements (and most of the recommended ones), the game didn't have this issue during the first two or three weeks of playing, and I haven't been experiencing problems with my other games.


Here's the file with my DXDiag information. Attachment 936


So far, I've done the following to try and fix the issue:

- Toggling shader detail, effect detail, and model/texture detail between medium and low. Haven't tried these as I high, since I doubt setting them higher than the game recommends would help.

- Tried toggling vsync. It runs similarly whether it's enabled or disabled, though I think I notice things looking a bit less choppy with it enabled.

- Tried all 3 multicore rendering settings

- Lowering the film grain amount

- Restarting my computer

- Temporarily disabling my antivirus. I even uninstalled antiviruses I wasn't using, in case they were running in the background without my knowledge.

- Lowering sound quality

- Disabling Wireless Zero, as this thread suggests

- Verifying the integrity of the game cache and defragging L4D2. The very first time I tried these, it seemed to help. Every subsequent time doing so did nothing, so I assume the better performance after that first time was unrelated.

- Defragging my whole computer

- Disabling steam community while in-game

- Disabling all my addons

- Updating to the latest graphic card drivers (266.58)

- Tried playing around with my graphic card settings located in the NVIDIA control panel.

- Downloaded game booster, and tried playing the game with it enabled. At first, this seemed to make the framerate drop happen a bit less often (around every 20-30 minutes), but then it went back to occurring at the usual intervals (5-10 minutes). This might've just been coincidence, since there have been a few times in the past where I noticed the framerate drop occurring less frequently.


As you can see, I've tried most of the usual fixes. You might've noticed I didn't do anything with multicore rendering, though that's because my computer has a single core, so the multicore rendering option's grayed out in the menu.

The only thing I can think of trying that I haven't is installing service pack 3, though I'm a bit reluctant to do so, since I've heard multiple people saying it makes your computer less stable, and causes issues.

So yeah, hopefully one of you can help me in solving this issue. The game's still playable as-is, though it sucks when I lose most of my healthbar, or fail in incapping a survivor solely due to a sudden and seemingly random drop in framerate.

That also happened to me in a game of Hard Rain :/ Every 5-15 minutes or so the game would be SUPER laggy and then go back to normal. But strangely enough, in other levels it stopped...Like me and the three other players went to The Parish after Hard Rain, the problem stopped for me.

Yeah, Even before this current issue of mine started occuring, I've noticed some stuttering in Hard Rain, though I assumed that might've been related to the weather effects, since for me, it was only occuring for a second or two, and seemed to usually happen with the lightning strikes.

Either way, I'm pretty sure that's different from the issue I mentioned in the thread, since these lag spikes I'm having are happening on every single map I'm playing, both official and user-created, and it's more severe than what what I observed happening in Hard Rain. Still though, I appreciate the suggestion.

I have the same issue, and it's been bothering the shit out of me. I tried many of the things you did, turning off V sync, allowocating low memory, game booster, even port forwarding... nothing helps. So frustrating