Got a problem.

I have a four-year old iMac 6,1 running with an Intel Core 2 Duo, 2.16 ghz, an NVidia GeForce 7300 GT (128 mb video memory) and 1gb ram.

I got L4D2 to run ... but it runs veeeeeeeerrrrrrrrrrrrryyyyyyyyyyyyy slowly. The opening video plays smoothly. Everything on the menus runs fast. The game itself is almost running backwards.

Min Sys Req for L4D2 is:

Processor: Pentium 4 3.0GHz

Memory: 1 GB for XP / 2GB for Vista

Graphics: DirectX 9 compatible video card with 128 MB, Shader model 2.0. ATI X800, NVidia 6600 or better

How does an Intel Core 2 Duo stack up to a Pentium 4 3.0? Is my Intel good enough for this game?

It seems my NVidia ought to be good enough ...

Is it a RAM problem? Do I need more ram?

I suspect this is a hardware rather than software problem.

In case you're wondering: yes, I tried ALL the Tips & Tricks.

You don't say what version of Mac OS X you're running. In general, the graphics performance has improved with newer versions, although there is some chatter about the very latest update of Snow Leopard (to 10.6.3) causing performance problems with Nvidia GPUs.

Also, although it's not in the Tips & Tricks, the obvious first place to go to try to increase performance is to the game's video settings. Turn the resolution and all of the advanced settings down to their minimum. If you still get miserable frame rates, then we definitely have to look elsewhere. If you get playable rates, then gradually turn settings up, one at a time, until it gets too slow.

Your CPU should definitely be sufficient. The GPU is, I would say, borderline. You can try running L4D2 in a window with Activity Monitor visible behind it. If a wineloader process is using about 100% of a CPU core, then that probably means the graphics driver is rendering in software because the game is using features not supported by the GPU hardware. If the memory pie chart is nearly all red and yellow with very little green or blue, then more RAM would probably help. Likewise, if disk activity is high when the level is not loading, then that probably represents virtual memory paging, which also suggests that more RAM would help.

Wow, Ken! Thanks for the reply. The part about the Activity Monitor is very helpful. I didn't know about that.

I'm running 10.5.something (I'll check when I get home). I keep it up to date, so it's probably whatever was just below 10.6. I've wondered if updating to 10.6 would improve things. I've heard 10.6.4 is supposed to have some improvements to graphics drivers, but I'm waiting to see.

I did turn all the video settings to minimum and tried windowed mode, but it was still very choppy and kinda going a frame or two - wait - frame or two - wait etc.

I'll try that activity monitor.