I am having trouble with Crysis, do you have any tips?

Basic Computer Performance:

* Latest drivers for your video card, motherboard, sound card can improve things greatly at times.
* Make sure you are running the beta drivers for nvidia cards and running the 1.2 patch for Crysis
* Defrag your hard drive. It's preferable to defrag 'before' installing so that the files stay close together and contiguous.
* If you only have 512MB or 1GB memory, 2GB is highly recommended.
* Go into your driver control panel to make sure ant aliasing(AA) or anisotropic filtering(AF) is not enabled unless you want them to be, they effect performance alot. Also you can change texture filtering quality to provide more performance in the drivers.
* If you are running Vista make sure to be using the current hot fixes, some effect performance and memory usage tremendously. Nvidia has a great list of recommended ones here: Vista hot fixes
* A video card like an 8800 GT for ~$250 will provide tremendous results if you haven't upgraded in a long time.
* Disabling any unneeded running process, especially antivirus, while playing is recommended.

Video Memory:

Using beyond the amount of memory that is locally on the video card will produce performance problems like stuttering and hitching due to having to fetch data from system RAM over the much higher latency PCI express bus. In other words, adjust settings/resolution in the game not to exceed your video RAM, otherwise you will experience overall performance issues and the periodic flickering of geometry and LOD's as it streams in. The game is very video memory intensive. Resolution and AA effect the amount of video memory the game uses tremendously. Here is a breakdown of video memory across different settings and resolutions.

* Windows XP
* Nvidia Driver 169.01

1280x1024 medium
* NoAA 184MB
* 2xAA 295MB
* 4xAA 355MB
* 8xAA 395MB

1280x1024 high
* NoAA 315MB
* 2xAA 375MB
* 4xAA 440MB
* 8xAA 470MB
-Texture medium-
* NoAA 300MB
* 2xAA 363MB
* 4xAA 423MB
* 8xAA 445MB

1680x1050 medium
* NoAA 223MB
* 2xAA 375MB
* 4xAA 455MB

1680x1050 high
* NoAA 368MB
* 2xAA 456MB
* 4xAA 535MB
-Texture medium-
* NoAA 340MB
* 2xAA 428MB
* 4xAA 505MB

1920x1200 Medium
* NoAA 240MB
* 2xAA 430MB
* 4xAA 535MB

1920x1200 High
* NoAA 400MB
* 2xAA 515MB
* 4xAA 615MB
-Texture Medium-
* NoAA 370MB
* 2xAA 475MB
* 4xAA 585MB

AA clearly makes a large impact in video memory. Different game levels may change these numbers. Changing textures from medium to low makes no appreciable difference since it is still using the low spec pack. The devs have made huge advances in optimizing this area since earlier builds of the game, either that or the textures are quite lower in quality, in fact these are the numbers medium textures used to give as if high textures are missing. Final shipping game may reflect differences here, will update accordingly. The textures setting alone no longer makes the difference it did in earlier builds regardless of high/medium/low setting, which again seems to give some indication higher textures have been removed temporarily or entirely.

Breakdown by video card memory:

256MB Video - 1680x1050 medium without AA or 1280x1024 medium with AA.
8800 GTS 320MB - Handles up 1680x1050 medium no aa, can go to high with some thrashing. Only AA at 1280x1024 looks to be viable with that memory limit.
512MB Video - Comes into its first wall at 1680x1050 4xAA on high. Performance and not memory will impact you here.
8800 GTS 640MB - Handles up to 1920x1200 4x AA (All High). performance makes that out of reach on today’s HW.
768MB and above - Memory will not be your limiting factor unless going to 2560x1600 with AA. Your GPU handling the raw processing of the geometry and shaders at that high resolution will be out of reach. I don't doubt that 1GB can be reached by tweaking Crysis and high resolutions with max AA on tomorrows HW. I already have found ways to approach 650MB at only 1280x1024.