Utility Partition and is not required for normal operation of the System.
Usually only 32MB
The partition is there so that the Diagnostics & EISA Configuration can be run without using a boot Disk. The EISA Configuration is a utility that came on a floppy dick with your pc and it is used to configure your system if there is an ISA or EISA device, it writes itself to that partition. Or if you run Dell Diagnostics which is on 5 floppy disks ( why they dont have it on a cd is beyond me) , they write themselves to this partition.
It may be that Your EISA partition contains a snapshot of your system.