Guys, i think i found the IDT chip:
http://www.idt.com/?partID=89HPES16T4G2ZABXG
I made out alot of the code, 89HPES16T...then i spotted BXG, so this might be the chip. It's generation 2.0 PCI-E spec. thus it is 16x, it must control the two 4x slots and the 8x slot...making 16x, the top PCI-E slot is 16x...how many lanes does P45 have?
It must be controlling the two 4x slots (8x lanes), then the PCI-E LAN chips...i see three on the PCB but the I/O shows four LAN ports, it must also be controlling the SATA ports as well and maybe the Silicon Image chips...that would eat 16x lanes easy.