We need the make/model of your computer. M9210 isn't listed at the IBM/Lenovo webiste. I can only guess that the slot is for a riser board. EDIT: I may have found it. Could it be a ThinkCentre M52 9210? If it is, the slot is probably an ADD 2-R
http://www-307.ibm.com/pc/support/s...
IBM part # 39J9334 PCI-e DVI-D Connection adapter, ADD 2-R