I have had terrible trouble with 7.4.2 and 8.1.0 on a Dell XPS9360. Whether booting from the KNOPPIX DVD (burn iso) or from a boot USB (I use Pendrive's Universal-USB-Installer v. 1.9.8.0, there may be other or later versions) all I got was a blank screen. But a certain amount of whirring suggested to me that the live version was in fact progressing and available. After a lot of messing about with vga=xxx in the KERNEL stanza in /boot/isolinux/isolinux.cfg I iterated to the best, sparsest and most portable version of this configuration file that I have EVER had. It reads
DEFAULT console
TIMEOUT 40
PROMPT 1
LABEL console
KERNEL linux
APPEND initrd=minirt.gz vga=893 lang=uk 1
LABEL video
KERNEL linux
APPEND initrd=minirt.gz vga=893 lang=uk #
By portable I mean this works on an ancient (really ancient) Samsung, any number of Dells in all configurations / ages, likewise Fujitsus. All screens from 800x600 to 1920x1080.
Still can't get 8.1.0 to work using a boot USB (DVD is fine). The architecture dictated by Pendrive leads to a configuration location error ("Can't find ..") from the very start. Even mimicking the geography of the 7.4.2 boot USB does not mend this.
Fergus
Dell PowerEdge T420 2x Xeon E5-2430 V2 2.50GHZ 32GB DDR3-1600MHZ 2x 550W PSU
$149.95
DELL R630 SERVER 8 x 2.5'' 2X E5-2680V4 32GB RAM IDRAC ENT & NDC 2X 495W PSU
$169.95
Dell PowerEdge R620 Server 2x E5-2660 v2 2.2GHz 20 Cores 256GB RAM 1x 480GB SSD
$139.99
Dell PowerEdge R730XD 28 Core Server 2X Xeon E5-2680 V4 H730 128GB RAM No HDD
$389.99
Dell PowerEdge R630 Server 2x E5-2640v3 2.60Ghz 16-Core 64GB H330
$182.65
Dell PowerEdge R620 Server - 256GB RAM, 2x8cCPU, 120Gb SSD/3x900Gb SAS, Proxmox
$320.00
Dell PowerEdge R720xd 26HDD 300gb 2.5-inch E5-2697 X 2CPU 384RAM 7.2 Tb HDD 
$180.00
Dell Poweredge R620 2x E5-2680 2.7ghz 16-Cores / 128gb / H710 / 2x Trays / 750w
$199.99
Dell Poweredge R730xd 3.5 2x E5-2690 v3 2.6ghz 64gb H730 14x Trays 2x 1100w
$489.99
DELL PowerEdge R730 Server 2x E5-2698v4 2.2GHz =40 Cores 128GB H730 4xRJ45
$601.00