It looks like Precision 5820 uses the Skylake-W Xeon CPU.
http://i.dell.com/sites/doccontent/shared-content/data-sheets/en/Documents/Precision-5820-Tower-Spec...
Does clicking on "Ignore" not let you proceed to install?
My guess is this current version installation checks for CPU family/model/stepping. With the 14.0.0, PCs with unsupported Intel CPUs (CPUs from Nehalem generation or older) which did not have the VMX unrestricted guest feature, could install but not able to power up any VM. You could try downloading an earlier 14.x version such as the original 14.0.0 if clicking on ignore does not let you proceed. And then do an update to 14.1.2 after the install.
https://my.vmware.com/web/vmware/details?productId=686&rPId=23139&downloadGroup=WKST-1400-LX
As for actual issues you might face if indeed the Skylake-W family/model/stepping is not recognised by Workstation 14.1.2, a telltale sign is the codename in the vmware.log will likely appear as Pentium (for Intel CPUs).
vmx| I125: hostCPUID codename: Pentium Core -- Unknown codename
If any of your VMs require virtualised performance counters to be enabled it will fail to power up. I have seen this with Workstation 12.5.x and Fusion 8.x encountering this problem with Kaby Lake CPUs. Another problem spotted is Oracle Enterprise Linux VM fails to boot as it tries to load DTrace modules (presumably somewhat related to the virtualised performance counters) and the DTrace module had to be uninstalled from the VM.
But other than this, in general, it appears the host CPU capabilities looks to be are recognised/identified (e.g. AVX2 instruction set) and initialised (e.g. EPT) by Workstation properly.
If you are able to run a VM on this Precision 5820, it will be interesting to see if it Workstation 14.1.2 identifies the AVX512 instruction set. But I think in general, instruction set does not require special setup by the hypervisor to be exposed to the VM; unlike advanced virtualisation features like EPT, unrestricted guest, virtualised performance counters requires extra work on the part of the hypervisor.
