Dell OptiPlex 980 SFF vs. Dell XPS 8500
Comparison and Differences
Differences between Dell OptiPlex 980 SFF and Dell XPS 8500
If you are looking for a more modern desktop, then you should go with the Dell XPS 8500 which was released in 2012. The Dell OptiPlex 980 SFF is older and entered production in 2010.
If you are looking for the smaller form factor the Dell OptiPlex 980 SFF is the right one for you. It is smaller than the Dell XPS 8500 and will fit more easily under your desk.
Processor
Usually the newer the generation of the CPU, the better the performance and efficiency is. If your budget allows it, you should go with the Dell XPS 8500 as it is running a newer generation CPU. This is not to say that Dell OptiPlex 980 SFF is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
Both models have have equal amount of ram slots (4 RAM). Usually two RAM slots are more than enough for most cases. However, the count should be taken into account when planning how much and what combination of RAM you are going to need for your system.
The Dell XPS 8500 is using the faster 1600 MT/s RAM. The Dell OptiPlex 980 SFF is slower by supporting RAM speeds of up to 1333 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Dell XPS 8500 as it has the ability to run 32 GB of RAM. The Dell OptiPlex 980 SFF can do a bit less at max 16 GB. Most of the times, this should be sufficient for the majority of users.
Ports
In total the Dell OptiPlex 980 SFF has 10 USB ports. The Dell XPS 8500 is inferior in this regard and packs 9 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. None of the desktop models has a USB 3.1 port (10Gb/s), so if you need a fast connection to your peripherals, like external Solid State Drive, you will need to look elsewhere.
Unfortunately, only the Dell OptiPlex 980 SFF has a DisplayPort. The Dell XPS 8500 does not have one? Don't worry though, nowadays video adapters are cheap and you can get almost any combination of conversion types.
The Dell XPS 8500 comes with an HDMI port, while the Dell OptiPlex 980 SFF does not support the interface. Of course missing HDMI port is something that can be easily fixed with a good adapter (e.g. DisplayPort to HDMI).
SATA ports are placed on the system board and it is where you connect your HDD, SSD and Optical Disk Drives. More SATA slots will allow you to have more drives running at the same time. In this regard the Dell XPS 8500 is better equipped as it comes with 4 SATA slot(s), while the Dell OptiPlex 980 SFF has 3 slot(s).
M.2 SSD interface allows you to transfer data with higher speeds compared to the old SATA interface. Unfortunately, neither the Dell OptiPlex 980 SFF, nor the Dell XPS 8500 has one. However, you can still use a SATA SSD drive which should give you satisfactory performance.
Make sure that the available M.2 slot supports the PCIe (also called NVMe) interface. This is important as there are M.2 slots which support only the inferior SATA III interface. For comparison, the SATA III interface has max speeds of 6Gb/s, while the PCIe 3.0 x4 will support speeds up to 32Gb/s!
Power Supply
Having a Power Supply Unit with high power rating is important, if you are going to use components which require extra power. The Dell OptiPlex 980 SFF comes with a decent 235 Watt PSU, but the Dell XPS 8500 has a more powerful one rated at 460 Watts. Choosing either one depends on your specific requirements and use case. Also don't forget that some models might have more than one PSU option - try to always get the most powerful one, especially if you plan to upgrade to a powerful GPU.
Motherboard
