Dell PowerEdge R740 vs R640: which refurbished server fits?

The PowerEdge R640 and R740 are the same 14G server in two different chassis — same CPUs, same DIMM slots, same iDRAC9. On the refurbished market, the choice comes down to rack units, drive bays, PCIe slots, and how much cooling headroom your workload actually needs.

Same 14G platform, two different chassis

Both servers launched in mid-2017 as part of Dell EMC's 14th-generation PowerEdge line. Each takes two Intel Xeon Scalable processors — first generation (Skylake-SP, 61xx/81xx) or second generation (Cascade Lake, 62xx/82xx) — up to 28 cores and 205 W TDP per socket, on the Intel C620 chipset with iDRAC9 management. Each has 24 DDR4 DIMM slots supporting RDIMM and LRDIMM up to 3 TB, at up to 2933 MT/s with 2nd Gen CPUs, plus optional Intel Optane DC persistent memory. The full processor matrix is in our R740 supported CPU list — the same SKUs apply to the R640.

Because the compute platform is identical, a dual Gold 6248 R640 and a dual Gold 6248 R740 benchmark the same. What you are choosing between is chassis capability: the R640 is a 1U density play, the R740 is a 2U expansion play.

Dell R740 vs R640: side-by-side specifications

Sources: Dell EMC PowerEdge R640 Technical Guide and PowerEdge R740/R740xd Technical Guide (Rev. A09).

PowerEdge 1U vs 2U: density against expansion

The R640 exists to pack two sockets and 24 DIMMs into one rack unit. A 42U rack holds roughly twice as many R640 nodes as R740s, which matters when you pay per U of colocation space or need maximum vCPU count per rack. The trade is I/O: three PCIe Gen3 slots is enough for a dual-port 25GbE NIC, an HBA, and one more card — and that is the ceiling.

The R740 spends its extra rack unit on expansion. Up to eight PCIe Gen3 slots across three riser positions, double the 2.5-inch front bays, higher-wattage PSU options, and the thermal room to run 300 W accelerators. If a node will ever need a double-width GPU, a multi-card NIC stack, or more than twelve drives, the 2U chassis is the only one of the two that gets there.

• R640: compute density — virtualization hosts, HCI nodes, web/app tiers, anything scaled horizontally.
• R740: expansion headroom — GPU inference, storage-heavy VM hosts, backup targets, mixed-workload standalone servers.

Drive bays and storage controllers

The R640 ships in three front configurations — 4× 3.5″, 8× 2.5″, or 10× 2.5″ — with an optional 2× 2.5″ rear bay for boot or cache drives, and up to 10 direct-attach NVMe on the 10-bay NVMe backplane. The R740 doubles the small-form-factor count with 16× 2.5″ or trades capacity per spindle with 8× 3.5″ bays.

If neither is enough, the PowerEdge R740xd extends the same 2U platform to 24× 2.5″ or 12× 3.5″ up front, plus mid-bay (4× 2.5″/3.5″) and rear-bay (4× 2.5″ or 2× 3.5″) options — a maximum of 32× 2.5″ or 18× 3.5″ drives, with up to 24 NVMe.

Controller options are common across the family: PERC H330/H730P/H740P, later H750, software-RAID S140, HBA330 for pass-through (ZFS, vSAN, Ceph), and the BOSS module with 2× M.2 SATA for a mirrored boot volume that keeps all front bays free for data. Check the R740 compatible drives list before ordering — SAS/SATA/NVMe support depends on the backplane installed, not just the chassis.

GPU and riser configurations

This is the hardest line between the two. The R740 supports up to three 300 W double-width GPUs or six 150 W single-width GPUs, fed by riser combinations that provide up to eight PCIe Gen3 slots with a maximum of four x16 links. GPU-enabled builds require specific riser configurations and the higher-wattage PSUs, so verify both on any refurbished unit advertised as GPU-ready.

The R640 officially supports up to three single-width accelerators of the NVIDIA T4 class (70 W, low-profile). That covers light inference and VDI encode offload, but no double-width card — no RTX-class, no V100/A100 — fits or cools in the 1U chassis.

Power, cooling, and noise

Both use the same hot-plug redundant PSU family, but the R740 extends to 2000 W and 2400 W Platinum units for GPU-loaded builds; the R640 tops out at 1600 W, which is ample for any CPU/storage configuration it can hold. For typical dual-Gold, 256 GB, SSD-based refurbished builds, the 750 W Platinum pair is the standard fitment in either chassis.

On acoustics, physics favors the 2U box. The R740's six 60 mm-class fans move the same air at lower RPM than the R640's up-to-eight small-diameter 1U fans, so the R640 runs noticeably higher-pitched under load. Dell's own guide rates the R740 quiet enough for office environments in typical configurations, with noise rising once you add more than two PCIe cards, GPUs, or NVMe drives. For a lab, closet, or office deployment, the R740 is the more tolerable neighbor; in a datacenter aisle it is irrelevant.

Typical refurbished pricing

Refurbished 14G pricing is configuration-driven — CPU pair, DIMM count, and drives move the total far more than the chassis does. As of mid-2026, chassis-for-chassis at equal specs, the R740 typically carries a modest premium over the R640, and the R740xd a further premium over the R740. Rough market bands (verify current quotes):

• Entry builds (dual Silver 41xx, 64–128 GB, no drives): the R640 is usually the cheapest dual-socket Scalable node available.
• Mid builds (dual Gold 61xx/62xx, 256–384 GB, SSDs): both land in the low four figures; the gap between chassis narrows as components dominate the price.
• Loaded builds (high-core Gold/Platinum, 512 GB+, NVMe or GPU): R740/R740xd only, and drives or GPUs become the largest line item.

Because DDR4 RDIMMs and Scalable CPUs are abundant on the secondary market, buying a lean configuration and upgrading later is a viable strategy on either platform. Current configurations and pricing are in our servers catalog.

R740xd vs R740: when the xd is worth it

The R740xd is the same board, CPUs, memory, and riser architecture as the R740 — the difference is storage density. It adds mid-chassis and rear drive cages on top of a deeper front backplane, reaching 32× 2.5″ or 18× 3.5″ drives versus the R740's 16 or 8. It is also the NVMe platform of the pair, with up to 24 NVMe drives in the 24× 2.5″ chassis.

The trade-offs: GPU and FPGA options on the R740xd are limited to the 24× 2.5″ chassis (and a maximum of two GPUs on NVMe configurations), the mid-bay displaces airflow, and the loaded chassis weighs about 33 kg / 73 lb. Choose the R740xd for software-defined storage, backup repositories, and Ceph/vSAN capacity nodes; choose the plain R740 when you need PCIe and GPU flexibility more than spindles.

Choose the R640 if / choose the R740 if

Both platforms use the same CPUs, memory, and management stack, so a mixed fleet stays operationally uniform — spare DIMMs, processors, and PSUs interchange. Browse tested configurations of both in our servers catalog.

Related reading: Is buying a used server safe? · Cisco Catalyst 9300 vs 9200

Frequently asked questions

Do the R640 and R740 use the same CPUs and memory?

Yes. Both are 14G dual-socket platforms supporting the same 1st and 2nd Gen Intel Xeon Scalable processors up to 28 cores and 205 W TDP, and both have 24 DDR4 slots for RDIMM/LRDIMM up to 3 TB at 2933 MT/s. CPUs and DIMMs interchange freely between the two, which simplifies spares for a mixed fleet.

Can the Dell R640 run a GPU?

Only single-width, low-power cards. Dell lists support for up to three single-width accelerators of the NVIDIA T4 class (or one FPGA) in the R640. No double-width GPU is supported in the 1U chassis. For 300 W double-width cards — up to three of them — you need the R740 with the appropriate riser configuration and high-wattage PSUs.

What is the difference between the R740 and R740xd?

Storage density. The R740xd adds mid-bay and rear drive cages and a denser front backplane: up to 32× 2.5″ or 18× 3.5″ drives and up to 24 NVMe, versus 16× 2.5″ or 8× 3.5″ in the R740. Compute is identical. The trade-off is that R740xd GPU options are restricted to the 24× 2.5″ chassis and capped at two GPUs on NVMe configurations.

How many drives fit in a PowerEdge R640?

Up to 12× 2.5″ total: front configurations of 4× 3.5″, 8× 2.5″, or 10× 2.5″, plus an optional 2× 2.5″ rear bay. With the NVMe backplane, up to 10 of the front drives can be direct-attach NVMe. The rear bay is commonly used for boot or cache SSDs, or you can fit a BOSS M.2 module and keep every front bay for data.

Which is louder, the R640 or the R740?

The R640, generally. Its 1U chassis uses up to eight small-diameter fans that spin faster and at a higher pitch to move the same air the R740 moves with six larger fans. Dell rates the R740 as office-tolerable in typical configurations, though adding GPUs, NVMe drives, or more than two PCIe cards raises fan speeds on either platform.

Is a refurbished R640 or R740 still worth buying in 2026?

For most general-purpose workloads, yes. The 14G platform offers iDRAC9 management, 2nd Gen Xeon Scalable performance, and abundant cheap DDR4 and spare parts on the secondary market — at a fraction of current-generation cost. Confirm firmware support status and buy from a vendor that tests components and includes a warranty before deploying to production.