Não acho que a performance do demo vai estar tão diferente da do beta.
O consumo de memoria parece que diminuiu bem ( 500MB comparando os requisitos do Beta e do Full )
Mas os processadores não tiveram mudanças tão drasticas, as Vgas até que parecem ter tido uma otimização legalzinha.
Segue os requerimentos do Beta e do Full pra comparações ( Minimos )
Crysis Beta System Requirements
The following was flagged as the minimume requirements for the beta only. These will change for the demo and release.
* Windows XP. This Betatest can be played on Vista but Vista is not officially supported.
* Intel P4 3.2 GHz/AMD Athlon 3200+ or higher
* 1.5 GB RAM
* 8X or faster DVD-ROM drive
* 4 GB or more of free hard drive space
* DirectX 9.0c, NVIDIA 7... series/ATI X... series or higher video card
* DirectX 9.0c compatible sound card
* Multiplayer: 2 to 32 players, network or Internet connection required (Cable, DSL, or faster connection)
Minimum system requirements
from Crytek and EA
OS - Windows XP or Windows Vista
Processor - 2.8 GHz or faster (XP) or 3.2 GHz or faster* (Vista)
Memory - 1.0 GB RAM (XP) or 1.5 GB RAM (Vista)
Video Card -256 MB**
Hard Drive - 12GB
Sound Card - DirectX 9.0c compatible
* Supported Processors: Intel Pentium 4 2.8 GHz (3.2 GHz for Vista) or faster, Intel Core 2.0 GHz (2.2 GHz for Vista) or faster, AMD Athlon 2800+ (3200+ for Vista) or faster.
** Supported chipsets: NVIDIA GeForce 6800 GT or greater; ATI Radeon 9800 Pro (Radeon X800 Pro for Vista) or greater. Laptop versions of these chipsets may work but are not supported. Integrated chipsets are not supported. Updates to your video and sound card drivers may be required.
Bom, isso sou eu que estou dizendo, posso estar errado. ( Menos os requerimentos

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