Thank you for posting on the Intel® communities.
Just to make sure, when you mentioned "p4600" do you mean Intel® Celeron® Processor P4600?
If the answer is yes, the number of displays supported for this processor is 2 based on Product Specifications available on https://ark.intel.com/ under "Processor Graphics".
However, to confirm how many displays are supported for this Fujitsu* system, we recommend you to double-check the Fujitsu* Datasheet with their support team so they can provide accurate information.
Also, since the "Intel® Celeron® Processor P4600" and "Intel® HD Graphics for Previous Generation Intel® Processors" have been discontinued, Intel Customer Service no longer supports inquiries for it, for additional inquiries perhaps fellow community members have the knowledge to jump in and help. You may also find the Discontinued Products website helpful to address your request. Thank you for understanding.
Also, if this inquiry is also related to another processor model (Intel® Pentium® Processor P4700), it is worth mentioning that the graphics in the Intel® Pentium® Processor P4700 has been also discontinued and Intel Customer Service no longer supports inquiries for it.
Intel Customer Support Technician