Thank you for your reply! I did some more digging and since FreeNAS is built off of FreeBSD the hardware supported is the same.  I couldn't find a list for FreeNAS specifically so I looked at FreeBSD.  I was still confused about the hardware and decided to go ahead with the poweredge 840, for two reaasons, it already has 8GB ram and it is not as hefty to be moving about (as compared to the 1900). I did pull the raid controller (to simplify things) and I plugged in three 250gb SATA drives and one 40GB SSD drive.  I did have to adjust the bios for the usb to be recognized, and also had to adjust it to be seen as a hardrive, then had to set the boot sequence for the usb drive acting as a hardrive.  Once all that was said and done I wrote my image of FreeNAS to my usb drive and booted up. It took maybe 10 minutes and I was up and running (once I had the hardware and bios configured), I created a RaidZ (as FreeNAS suggested) and with my three 250GB drives it produced 453GB of usable storage space.  The 40GB SSD is used as L2ARC (from my understanding cache), I tried the setup with and without the 40GB SSD.  The difference was impressive, just from opening photos or streaming video to my Win 8.1 (Dell 17r) laptop is almost seamless, as if the files were stored locally.  I was impressed at how quick and easy FreeNAS is to use, simple and quick network shares can be setup with permissions that just work in under 5 minutes.  I am not putting Windows Server down but typically configuring active directory takes a bit more effort.  I am satisfied for now and will continue to experiment with the Poweredge 840 before I commit to a processor upgrade.  Once I acquire 16GB of memory for my Poweredge 1900 I will proceed with it, as it only has 1GB right now, crazy.  Thank you for your assistance.
I have searched these forums and the web in general for a concise answer to my questions but to no avail.  I cannot simply seem to find anyone who is using 'older' technology and repurposing it as much as one would think (I am a broke college student by the way).  I purchased a Poweredge 1900 & a Poweredge 840 Server from ebay about this time last year.  I have been busy and have yet to work with these two units.  I wanted to utilize the PE 1900 as a file server and then push a backup of those files to the off-site server, the PE840.  I had intended to purchase four 1TB or four 2TB SATA drives (WD Black or WD RED) for each sytem respectively. I was scrolling through some videos on youtube the other day and discovered FreeNAS.  This seems like a much better solution than using Ubuntu Server but it also made me think about the hardware Raid that these systems have.  If FreeNAS utilizes ZFS (software raid controller), then you would want to avoid a hardware raid controller. My current assumptions, please correct me if I am wrong on any of the following: I think that each one of these systems support drives up to 2TB?, I believe that I can use SATA drives and not SAS drives, four drives in each system. I believe that I can boot from USB flash drive (a fast one, that I intend on installing FreeNAS onto, which they recommend) I believe I can connect the drives to the Raid Controller/Perc controller(& just turn RAID 'off'), or just directly to the motherboard.  (What woud be the advantages/disadvantages of using the card or just using the board) I intend on working with what I have right now(cheap and available), then once I get this configuration working I will take it out of the sandbox/lab, upgrade the processors and ram to the max my budget will allow and go live with the setup (if it is even possible) As of now they sit in a corner begging to consume power, and polute the noise environment with their screaming fans (PE1900 specifically).  I know I could pursue other options but I already have these two units.  I really want to utilze FreeNAS for its file serving capabilities and ZFS for its reliability.  Can this be done with this equipment?, or should I junk them and move on?  
Poweredge 1900 and Poweredge 840, SATA HD's, FreeNAS with ZFS and NO hardware 
RAID