General Knoppix support for those who've read the FAQ at the Wiki
HP Z440 Xeon E5-1605 v3 2.8GHz 1TB SSD 32GB RAM DDR4 WIN10P
$148.95
Matched Pair Intel Xeon E5-2690v4 2.6Ghz 14-Core 135W 35MB LGA2011-3 CPU SR2N2
$45.99
HP Z420 Workstation Xeon E5-2690 2.9ghz 8-Cores / 32gb / 1TB / DVD / Win10
$94.99
Dell Precision T5810 Tower (Xeon E5-1650 v3 - 16GB RAM - K2200 - NO OS NO HDD)
$89.89
Intel Xeon E5-2680 v4 SR2N7 2.40GHz 35MB 14-Core LGA2011-3 CPU Processor
$14.99
Intel Xeon E5-2699 V3 2.3Ghz 18 Core 45MB LGA 2011-3 x99 DDR4 CPU Processor
$39.91
Intel Xeon E5-2699 v3 18 Core 2.3 GHz 45MB SR1XD LGA 2011-3 B Grade CPU
$36.95
Intel Xeon Gold 6138 2.0GHz 27.5MB 20-Core 125W LGA3647 SR3B5
$29.00
INTEL XEON PLATINUM PROCESSOR | 2.10GHZ | SR37A
$489.99
Intel Xeon W-2245 SRH02 3.90GHz 8 Core LGA-2066 CPU Processor
$314.95