Dell's Precision tower range runs from a single-socket desktop replacement to a dual-socket machine with four graphics slots. The model numbers do not make the ladder obvious. This page sets out what each tier actually gives you, so you can start from the workload rather than the part number.
The tier ladder
| Model | Sockets | DIMM slots | DIMMs per channel | Graphics slots | PCIe slot positions | Power supply options |
|---|---|---|---|---|---|---|
| Precision 3660 | One | 4 | 2 | 1 | 3 | 500W, 750W |
| Precision 3680 | One | 4 | 2 | 1 | 3 | 500W, 750W, 1000W |
| Precision 5820 | One | 8 | 4 | 2 | 5 | 425W, 685W, 950W |
| Precision 5860 | One | 8 | 4 | 2 | 5 | 750W, 1350W |
| Precision 7820 | One or two | 12 | 6 | 2 | 5 | 950W |
| Precision 7920 | One or two | 12 per processor, 24 with both fitted | 6 | 4 | 7 | 1400W |
Reading the ladder
The 3000 series is a workstation in name and a desktop in shape
Four DIMM slots across two DIMMs per channel, one graphics slot, three PCIe positions. That is a capable machine for single-application CAD, modelling and general engineering work, and it is the right answer far more often than people expect. What it is not is expandable: one graphics card, and a memory ceiling reached quickly.
The 5000 series doubles memory and graphics capacity
Eight DIMM slots across four DIMMs per channel, two graphics slots, five PCIe positions. This is the tier where a second GPU, a RAID controller and a capture or network card can coexist. The 5820 and 5860 share that shape; the 5860's 1350W power supply option signals the heavier graphics configurations it is expected to carry.
The 5820 has one characteristic worth knowing before buying used: it shipped on three different boards — Xeon W-21xx, Xeon W-22xx and Core X — and the processor family is fixed by the board. Core X configurations also narrow the storage path, with SAS unavailable on some builds and PCIe lanes limited for front NVMe on i9 and i7 parts.
The 7000 series is where the second socket appears
The 7820 brings six-channel memory and a second processor option. The 7920 goes further: four graphics slots rather than two, seven PCIe positions rather than five, and 24 DIMM slots when both processors are fitted.
The rule that catches people on both: the headline memory figure assumes two processors. A single-processor 7920 has 12 DIMM slots, not 24.
Choosing by workload
- Single-application CAD, Revit, modelling — the 3000 series is usually sufficient, and the money is better spent on clock speed and a good GPU than on a larger chassis.
- Large assemblies, simulation, multi-application work — the 5000 series, for the memory channels and the second graphics slot.
- Rendering, GPU compute, multi-GPU — the 7920, because it is the only tier in the range with four graphics slots.
- Memory-bound work: large datasets, heavy virtualisation — the 7820 or 7920, where six-channel memory and dual sockets apply.
What these figures describe
The table sets out what each platform supports as a design. It does not describe what is fitted to a particular refurbished unit, or what is currently available to configure. Processor count, populated DIMM slots and board variant all vary on the used market.
Where to go next
- Precision 5820, 7820 and 7920 compared side by side
- Precision 5820, 7820 and 7920 specifications
- Precision 3660, 3680 and 5860
- Precision 7920 compared with the HP Z8 G4
- Browse refurbished Dell Precision workstations
- Check memory options with the RAM Advisor
Hardware bought from TekBoost carries our standard 3-year warranty with Next Business Day part replacement, subject to the terms, exclusions and conditions on that page. If you would rather describe the workload than pick a model, request a quote.
If the work is CAD or BIM
Most workstation purchases in this range are driven by a specific application rather than by a model preference. Our CAD guide sets out what AutoCAD, Revit and similar workloads actually need — clock speed against core count, professional graphics, memory and storage — and compares Autodesk’s stated requirements with what works in practice.