I am having some issues with iconservices as well. I am running some automated testing that creates and deletes a lot of users accounts, and I found that Mavericks makes an entire new 500MB+ iconservices cache for each user. This quickly filled the drive of my VM and killed my automated tests.
The only info I can find anywhere about IconServices is a developer document that says it was deprecated a long time ago. I have tested 10.7 and 10.8 and IconServices is nowhere to be found on those versions.
These huge caches show up in:
/var/folders/(2 characters)/(64-bit encoded something)/C/com.apple.IconServices/
This folder is filled with tons of files ending in .iscachebmp
It appears a new copy of this huge folder is created for each user account created, each with difference random-ish paths inside the /var/folders/ directory.
For users with only one partition they'll probably never be aware of it (unless they use a disk space utility that will expose them).
However for anyone that has their disk divided in to partitions so that their OS is on a partition with around 15GB of overhead (as I thought I would have)... it is extrememly noticeable. And if a user only left approx. 10GB of overhead (i.e. Mountain Lions' size + 10GB)... they will need to move their OS to a different (i.e. larger) partition.
I installed Mavericks on a 10GB larger partition than Mountain Lion was on (50GB versus 40GB). But all of these 'mystery' files/folders took up almost all of the additional space.
I'd really like to know what Apple did to use up approx. 5-6GB of space that Mountain Lion never needed and that NO WHERE does Apple mention in any of its white papers, etc.
I recently upgraded to Mavericks (on a single partition) and am finding that IconServices is using more memory than any other application/service. It's well over half a GB.
I'd like some kind of explanation from Apple what this is doing. At the same time, I'm having very slow app and document icon loading; i.e., a blank document for a few seconds, or longer.
Very curious and annoyed by the icon slowness.