Here’s something I noticed when I started up Softimage 2014 SP2 for the very first time. It spent about 26 seconds writing some cachedat and cachehdr files in my User folder:

During subsequent startups, Softimage just reads in the cachedat, which takes a lot less time (eg < 0.005 seconds).

I looked back at my previous versions of Softimage, and it seems these cache files were new in 2014. There's actually two cachedat files, each with an associated cachehdr header. You'll find them in your %XSI_USERHOME%\Cache folder:

C:\Users\xsisupport\Autodesk\Softimage_2014_SP2\Cache\{870AB238-90C2-4336-8D46-B2CDD31C8A34}.cachedat
C:\Users\xsisupport\Autodesk\Softimage_2014_SP2\Cache\{870AB238-90C2-4336-8D46-B2CDD31C8A34}.cachehdr
C:\Users\xsisupport\Autodesk\Softimage_2014_SP2\Cache\{AD8CCDD2-C275-46E3-9881-265DB5BC84BB}.cachedat
C:\Users\xsisupport\Autodesk\Softimage_2014_SP2\Cache\{AD8CCDD2-C275-46E3-9881-265DB5BC84BB}.cachehdr

One cache is read at startup. The other is updated when you first drag an ICE node into an ICE tree (and then if you start a new XSI.exe session and drag the same node into an ICE tree, Softimage will read from the cache). Running strings on these cache files showed lots of ICE node/compound names, so they seem to be strictly for some sort of ICE-node caching (eg ports, layouts, logic, …).