Without knowing exactly how the machine depends, I'd say that it is
indeed correct, and nothing to worry about.
One thing that makes the "cache" number look large is that the cache is very
tightly shared with process pages, and essentially any code pages in memory
will generally be in the cache too. So it's not uncommon to have quite large
numbers for cache if you're running lots of programs: it doesn't necessarily
mean that the actual filesystem cache is very large, it can just mean that
there are lots of unmodified code pages in memory..
Linus