IIRC, the favorite GPU for playing Crysis at its time of release was the G92-based 8800GT 512MB and people would often pair it with either an overclocked Q6600 or a cheaper E8xxx.
That was good enough for ~30FPS non-maxed settings at 1024*768 or similar.
Here’s some thread digging for you:
I’m wondering if that gigabyte 8800 512 gt with the nice after market-looking cooler used with a e8400 or q6600 overclocked would yield a nice image at 1900×1200. That’s a kinda full sentence, maybe I’ll reiterate @1900×1200 Crysis -8800 512mb gt (overclocked) -q6600 (overclocked) or e8400…
In your case, it looks like that Xeon is pulling the 6800XT back a bit so you’re running into a bottleneck. OG Crysis is a DX9 game, so it’s a lot more single-threading dependent than modern games.