Huh? Interesting about the issues with the Steam version. I just tried and sure enough, Crysis won't launch for me. There was a Steam update to the game in 2023 which removed SecuROM. Might be related?
Crysis Warhead, however, does launch just fine. And that's basically a "standalone expansion" using almost the same game engine and everything from what I remember.
Crysis (original) gives me two options when launching, and one is blank. I tried both and get the same result. From quick searching, this seems to be the 32-bit and 64-bit choice. Supposedly the latter works for some people.
There seem to be workarounds, from setting Windows compatibility to older versions (apparently Windows 8+ is where this can break, but some people have it working fine), to using Crysis Warhead executable for Crysis, to trying 64-bit instead of 32-bit, to standalone launchers. I haven't tried any of that, besides the aforementioned "trying both options the game presents when launching" thing.
I'm not getting the Black screen and then crash that some people report. I just see a new (blank) icon begin to appear on the taskbar and then it immediately disappears without even going to launch/render anything.
I was a manager for a PC shop back then and remember well the differences in performance as we had to demonstrate such quite often. Single core CPU's with a very good GPU could offer a playable and steady 25 to 30FPS. But for fluid 60fps+, a high mhz dual core was required at minimum and a Quad was recommended. Crysis was our Core2Quad seller. It was an easy task to show differences with the in-store demo systems. It was night and day.
I'm not going to question your claim, because you have a high sample size from a business perspective you're pulling from on this so I'm sure you saw the results you claim, but I will say I do find those results interesting. I remember Crysis as being infamously thread limited, not core limited, and I do recall the E8x00 Duos outperforming the Quads due to clock speed disadvantage. I know my E8400/E8600 ran the games very, very well.
The real limiting factor was almost the graphics cards with this game anyway, not the CPU. Maybe with a Pentium 4 or similarly slow Athlon XP/64 single core CPU, would it be a bigger issue.
The first big game I really remember where quad cores showed big differences was the PC port of Grand Theft Auto IV.