Dell PowerEdge T320 performance drop - especially in IIS and through HTTP

We have a new Dell PowerEdge T320 running Windows 2012 R2 that has just had a huge performance decrease. All this server does is host a few websites in IIS.  Programs seem to take a very long time to open on this server in the past few days and when I attempt to run an internet speed test from that server I get a max of 1.2Mbps whereas an identical server hosting the database on that network gets 30Mbps down and 10Mbps up. If I transfer a file through a network share either to or from the slow server to the other identical server, I get around 90MB/s. If I access one of the websites internally using the internal IP of the website, it takes about 20 seconds before the page starts to load. Same deal from the outside world into the websites. This just started happening since about 3 days ago over the weekend when nothing was being done on the server and no changes were being made. Prior to this the server was extremely fast and responsive.

Things I've tried:
-Uninstalled the last updates that were installed from 5 days ago up until today
-Resynchronized the mirrored drives (running on PERC H310). All hardware checks within OpenManage seem to say everything is good
-Ran check disk and SFC scan
-Checked for IP address conflicts
-Restarted the Sonicwall firewall and the Comcast modem
-Tried booting into safe mode w/ networking and received the same results
-Updated all server drivers
-Disabled TCP offload on the network adapter
-Checked for viruses/rootkits
-Checked resource monitor. Disk queue never goes past 0.05 and CPU usage is around 5% usage and Memory stays around 2GB/32GB. Network doesn't go above 1Mbps unless I transfer a file through a network share, then it jumps up past 100Mbps
-Checked Event Viewer and didn't see anything that shed light on the situation. I do see a few "fatal communication error with the Windows Process Activation Service" but I'm not sure if that would have anything to do with the problems.

Any ideas on this one? What should my next steps be?

OAC TechnologyProfessional NerdsAsked:
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OAC TechnologyConnect With a Mentor Professional NerdsAuthor Commented:
I uninstalled ALL of the drivers in device manager and then restarted the server. It appears to be working now. The last drivers I uninstalled before things started working were the Processor drivers. No idea what was going on.
Aaron TomoskyTechnology ConsultantCommented:
Antivirus on the server? Are you plugged directly into the sonicwall or is there a switch involved? Any lag or nic teaming?

And my personal favorite: what else happened around the same time, however improbable it would be to have an effect? A new computer could have a static ip conflict or even mess with power.
OAC TechnologyProfessional NerdsAuthor Commented:
Antivirus is not running on the server. We are plugged into an HP Procurve gigabit switch, but I've plugged in the 2nd NIC on that server directly into the firewall with no difference. No NIC teaming.

That's the thing, the server was just sitting there on the weekend with no one in the office and no one logging in remotely.

Here's the best part: Just for fun I converted that server to a Hyper-V image and put it on the other (identical) server there. The image works perfectly fine. I'm running hardware diagnostics on the server that was having problems, but so far no problems have shown up. Still no idea what is causing this.
OAC TechnologyProfessional NerdsAuthor Commented:
Found solution
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