Using SSD as cache for RAID array in DL980 G7

[Swordsman20]

I am looking at purchasing a used HP DL980 G7 server with 8 10-core E7-4780 processors.  It is to be used for engineering simulation calculations requiring an SMP configuration, as opposed to a distributed-memory setup like a traditional cluster.  This setup will give me 80 physical cores across 8 processors, 512GB of RAM, running Centos 6.8.

I have eight (8) 2.5" hot swap drive bays available, 7 if I reserve one for a standalone boot drive.  I would like to use the others in a RAID 5 array and employ an SSD as a giant drive cache for the RAID array, which though fast compared to a single drive (reading, anyway) will be slow compared to just about any SSD.  The system comes with an HP Smart Array P410i - 1024MB, which supports both SAS drives at 12Gb/s and SATA at 6.0 Gb/s.

I am OK with using one of the 2.5" bays for the SSD and connecting it through the RAID controller but could also install a separate PCIe-based drive, though this system only supports PCIe 2.0. 

Does anyone have any good advice on the best way to accomplish what I want to do?  In addition to fast access in a read environment (write is less important in this case), I would like to have as large a capacity as I can overall without going to a separate drive array.  I am willing to swap out the RAID card if that is required and am also looking at XFS as a possibility.