The refurbished Dell PowerEdge T640 8-Bay 3.5" is the 14th gen flagship tower server: a 5U dual-socket platform carrying the full enterprise envelope (24 DIMM slots symmetric, up to 8 PCIe Gen3 slots, up to four 300W GPUs, NVDIMM-N persistent memory, and up to 2400W power supplies) in a tower chassis built for office and remote-site deployments that need datacenter-class compute without rack infrastructure. The 8-Bay 3.5" configuration is the one we reach for when bulk LFF capacity is the storage priority: eight hot-swap 3.5" front bays for SAS, SATA, or Nearline SAS drives alongside the platform's flagship compute envelope.

This is the right tower for branch-office virtualization hosts running 30 to 60 VMs, remote-site SQL or Exchange servers that need serious capacity, modest GPU-accelerated workloads such as CAD, inference, and VDI in office environments, and any deployment where rack space is unavailable but datacenter-class platform headroom is required. In positioning it is the tower equivalent of the R740 and R740xd: same socket, same memory topology, same PCIe envelope, same iDRAC9, in a rack-convertible tower chassis.

To configure a build, call 1-800-778-1545 or use the quote form on this page and we will respond within 24 hours. Every refurbished T640 ships after a 12+ hour burn-in covering every memory channel, every PCIe slot, and every drive bay, backed by our standard 180-day warranty with 1-Year, 2-Year, and 3-Year Premium options available. Volume pricing applies at 5 units and above.

Where the T640 8-Bay 3.5" Fits in the Family

The T640 sits at the top of Dell's 14th gen PowerEdge tower line, above the entry-tier Dell PowerEdge T340 8-Bay 3.5" entry tower (single-socket, modest envelope) and the mid-range Dell PowerEdge T440 8-Bay 3.5" tower (dual-socket, 16-DIMM asymmetric memory, 1 TB ceiling, single GPU). The T640 is the only 14th gen tower with the full flagship platform: 24 symmetric DIMM slots, a 3 TB memory ceiling, four-GPU support, eight PCIe Gen3 slots, and NVDIMM-N persistent memory.

Within the T640 chassis line we stock two configurations: this 8-Bay 3.5" LFF variant for bulk capacity, and the Dell PowerEdge T640 16-Bay 2.5" SFF configuration for IOPS-leaning, higher-VM-density workloads. The platform underneath is identical; the difference is the storage profile. Choose this 8-Bay LFF for file serving, capacity-tier databases, backup repositories, or a four-GPU build that also needs bulk local storage. Choose the 16-Bay 2.5" SFF when transaction IOPS, high VM count, or optional NVMe matter more than raw capacity.

Storage: 8 x 3.5" LFF Bays for Flagship-Tier Tower Capacity

The 8-Bay 3.5" chassis provides eight front-accessible hot-swap 3.5" drive bays for SAS, SATA, or Nearline SAS drives. The backplane is SAS/SATA only; this LFF chassis does not support front NVMe (NVMe lives on the 16-Bay 2.5" and specialist 24-Bay 2.5" variants). With eight 22 TB Nearline SAS drives, raw capacity reaches 176 TB; in RAID 6 with one hot spare, usable capacity lands near 110 TB. That is real bulk-storage density backed by the T640's flagship compute envelope, which matters when the tower does more than serve files: dense VM hosting with capacity-tier storage, SQL databases with multi-TB data sets, and application servers with large content stores.

For boot, the T640 uses a BOSS PCIe card (Boot Optimized Storage Solution) at the rear of the system: up to two 80 mm or 110 mm M.2 SATA devices in hardware RAID 1, the same BOSS-S1 module used across the R740 and R740xd. Putting the OS on BOSS keeps all eight front bays free for data and removes the OS from the data array entirely. IDSDM (Internal Dual SD Module) and an internal USB option exist for hypervisor-only boot, but BOSS is the right call for production. BOSS drives are cold-swap on this platform; replacement requires downtime.

Drive guidance for the 8-Bay 3.5": for bulk capacity we spec 12 TB, 16 TB, 20 TB, or 22 TB Nearline SAS 7.2K drives. RAID 6 is mandatory on any array of 8 TB and larger drives, because the rebuild window on large NL-SAS arrays carries real double-disk-failure risk. For mixed workloads, a SAS SSD pair (1.92 TB or 3.84 TB) for cache or hot data alongside six NL-SAS bulk drives is a clean layout. External SAS shelf expansion is supported through the H840 external controller for deployments that outgrow eight bays.

Storage Controllers: PERC H740P Is the Default

The T640 supports the standard 14th gen flagship PERC family in a dedicated controller slot that keeps all eight PCIe expansion slots free:

• PERC H740P (8 GB NV cache, battery-backed): the production default for write-intensive or mixed read/write workloads on this chassis.
• PERC H730P (2 GB NV cache, battery-backed): solid general-purpose choice for read-leaning workloads.
• PERC H330 (no cache): entry-tier hardware RAID for light workloads only.
• HBA330 (pass-through HBA): for software-defined storage stacks such as Storage Spaces Direct, Ceph, and ZFS.
• PERC S140 (software RAID via the C620 chipset): dev and test only. We do not quote S140 for production.
• PERC H840 (external, 8 GB cache): for SAS shelf expansion beyond the internal eight bays.

For the 8-Bay 3.5" our default recommendation is the PERC H740P. The 8 GB non-volatile cache earns its place on bulk-capacity workloads with mixed read/write patterns: backup-target ingest, file-server cold writes, and modest database transaction logging. For software-defined storage builds the HBA330 pass-through is the right call; the T640's eight PCIe slots make it workable as a tower hyperconverged node, though for serious clustered storage we still point customers to rack platforms.

Processors: 14th Gen Skylake-SP and Cascade Lake-SP

The T640 is built on Intel's LGA 3647 socket and takes up to two Xeon Scalable processors from the 1st generation Skylake-SP family or the 2nd generation Cascade Lake-SP family. Same socket, drop-in compatible with a BIOS update. For any new T640 deployment in 2026 we spec 2nd gen Cascade Lake: better performance per watt, hardware Spectre and Meltdown mitigations, and access to the widely available Refresh SKUs (Gold 6230R, Gold 6248R, Gold 6258R).

The platform supports up to 28 cores per socket (Platinum 8280) and accepts CPUs up to 205W TDP, meaningfully higher than the T440's 150W mainstream ceiling. Common specs: the Gold 6230 (20 cores, 2.1 GHz, 125W) for balanced virtualization and database workloads; the Gold 6248R (24 cores, 3.0 GHz, 205W) where clock speed matters; and the Platinum 8280 (28 cores, 2.7 GHz, 205W) for maximum-density VM hosting. Dual Gold 6248R is a common build for serious tower virtualization.

For the 8-Bay 3.5" specifically, the LFF bays bias the deployment toward bulk-capacity workloads where memory and storage matter more than raw core count, so dual Gold 6230 (40 cores total) is our most common spec, stepping to dual Gold 6248R (48 cores) for compute-heavier mixes. The T640's thermal envelope genuinely supports dual 205W CPUs without acoustic compromise; the chassis was designed for serious dual-socket operation and ships with the high-performance heatsinks those CPUs require. Single-socket configurations are supported but cut memory to 12 DIMMs and PCIe to three slots, which is rarely the right call on a flagship-tier tower; if single-socket is enough, the T440 is the better-positioned platform.

Memory: 24 DIMMs Symmetric, Up to 3 TB

The T640 has 24 DDR4 DIMM slots in a fully symmetric topology: CPU1 owns 12 slots, CPU2 owns 12 slots, six channels per CPU at two DIMMs per channel. This is the same flagship memory topology as the R740 and R740xd, and a real upgrade over the T440's asymmetric 10-plus-6 layout. Symmetric population gives NUMA-aware applications balanced per-socket bandwidth, which matters for VM density, large databases, and analytics.

Memory speed reaches 2933 MT/s at 1 DIMM per channel on Cascade Lake, dropping to 2666 MT/s at 2 DIMMs per channel under full population; mixed-speed configurations run at the slowest installed DIMM. Skylake-SP tops out at 2666 MT/s regardless. The 2933 ceiling at 1 DPC is a genuine delta over the T440's flat 2666 MT/s and matters for memory-bandwidth-sensitive workloads.

Maximum memory is 3 TB with 24 x 128 GB LRDIMMs (3DS); with 64 GB LRDIMMs or 64 GB RDIMMs the ceiling is 1.5 TB; single-socket configurations max at 1.5 TB across 12 DIMMs. We typically ship T640 systems in the 384 GB to 768 GB range for tower virtualization, stepping to 1.5 TB for serious VM density. The 3 TB ceiling is rarely needed outside in-memory database workloads.

NVDIMM-N persistent memory is supported: up to 12 x 16 GB NVDIMM-N modules (one per channel), totaling 192 GB of persistent memory. It requires both CPUs installed and follows specific population rules (NVDIMM-N may be mixed with RDIMM but not with LRDIMM). NVDIMM-N is genuine storage-class memory, flash-backed with a backup battery so data survives power events. This is unique to the T640 in Dell's tower line; the T440, T550, and T560 support no persistent memory in any form. For tower deployments running write-intensive transactional databases, SAP HANA, or Storage Spaces Direct with a persistent metadata tier, NVDIMM-N is the platform-justifying feature.

Networking and PCIe Expansion

The T640 ships with two onboard 10 GbE BASE-T LOM ports (Broadcom 57416), a meaningful step up from the T440's 2 x 1 GbE baseline. On a flagship-tier tower, 10 GbE is the standard rather than an upsell, and it is enough for most SMB and remote-site virtualization with iSCSI or NFS storage networking without adding a PCIe NIC.

For more, the T640 takes rNDC (rack Network Daughter Card) options including dual 10 GbE SFP+, dual 25 GbE SFP28 (Mellanox ConnectX-4 Lx), and quad-port 1 GbE. The chassis carries up to 8 PCIe Gen3 expansion slots plus a dedicated PERC slot with both CPUs installed; single-CPU configurations expose only 3 PCIe slots. That slot count is a real advantage over the T440's five slots and leaves room for 10/25/40/100 GbE NICs, HBAs, and GPUs together. For dense virtualization we typically pair the onboard 10 GbE with a 25 GbE Mellanox ConnectX-4 Lx card.

GPU Support: Up to Four 300W Accelerators

The T640 supports up to four 300W GPU accelerators, the strongest GPU envelope of any Dell tower in any generation (the 15th gen T550 maxes at two; the 16th gen T560 supports up to six but at lower per-GPU power). The four-GPU configuration is a chassis-level option that must be specified at purchase, because it requires specific cooling and PCIe routing that cannot be retrofitted. Qualified cards have included the NVIDIA Tesla V100, T4, A10, A30, A40, A100, and RTX series, plus AMD MI-series accelerators; the qualified-card list shifts over time, so we confirm it at quote time.

One platform constraint matters: with NVMe storage configurations the GPU ceiling drops to two cards. The 8-Bay 3.5" chassis is SAS/SATA only, so the full four-GPU envelope is available here. If a deployment needs both NVMe storage and four GPUs, the platform forces a choice and a rack platform is the better answer. The four-GPU envelope makes this chassis a real option for office-deployed GPU work: branch AI and ML inference, CAD render nodes for engineering offices, dense VDI (60 to 100 light desktops per host), and modest on-prem ML training. This is the T640's strongest differentiator over the single-GPU T440 and the clearest reason to choose tower over rack when the deployment specifically needs office-deployable multi-GPU compute.

Management: iDRAC9 Generation

Out-of-band management is iDRAC9, standard across 14th gen PowerEdge. We recommend the iDRAC9 Enterprise license for any production T640: virtual console redirection, virtual media, automated firmware updates through the Lifecycle Controller, group management via OpenManage Enterprise, and SupportAssist proactive diagnostics. iDRAC9 Express lacks virtual console and is insufficient for remote troubleshooting at branch or unattended sites, which is exactly where flagship towers tend to live.

The platform carries the full iDRAC9 security baseline: TPM 2.0, cryptographically signed firmware, Silicon Root of Trust, Secure Boot, System Lockdown (Enterprise plus OpenManage Enterprise), Quick Sync 2.0 mobile management, and System Erase data sanitization. For remote-site deployments with limited on-site IT, iDRAC9 Enterprise is the single most useful line on the BOM: remote console is what saves a site visit when something breaks.

Power and Cooling

The T640 supports a broader PSU range than any other Dell tower in our catalog. All are hot-plug and support redundant 1+1 operation:

The 750W pair handles non-GPU light builds; 1100W is the right default for dual-socket Gold-tier compute without GPUs; 1600W is required for two-GPU configurations; 2400W is required for four-GPU configurations. The 2000W and 2400W PSUs derate at low line (100 to 120V AC), so any two-GPU-or-greater build should run on 200 to 240V AC for full output. Dual hot-plug redundant Platinum PSUs are mandatory for production; Titanium-tier SKUs are available where efficiency targets call for them. Cooling uses a redundant fan configuration, which is what lets the chassis carry dual high-TDP CPUs and multi-GPU loads while staying office-acceptable in most builds. Four-GPU plus dual 205W CPU configurations will run noticeably louder.

Physical Specs & Platform Notes

• Form factor: 5U tower, rack-convertible with the optional rack conversion kit. Chassis depth roughly 726 mm; loaded weight near 35 kg with eight LFF drives and two PSUs. In rack mode it consumes 5U.
• PCIe expansion: up to 8 PCIe Gen3 slots plus a dedicated PERC slot with both CPUs installed; slots 4 through 8 require the second processor, and single-CPU builds expose only 3 slots.
• Parts availability: excellent. The T640 shares its platform, PERC family, BOSS module, iDRAC9, and PSUs with the high-volume R740 and R740xd, so spares and field-replaceable units are mature and widely stocked. Dell ProSupport on 14th gen is approaching end of extended support, so third-party maintenance is the standard production support path in 2026.
• Accessories we recommend: the BOSS-S1 boot card for production boot; the rack conversion kit if rack deployment is planned (sold separately, add it to the BOM up front); the iDRAC9 Enterprise license; and a 25 GbE Mellanox ConnectX-4 Lx NIC for dense virtualization.
• Platform notes: the LFF backplane is SAS/SATA only (no front NVMe on this chassis); BOSS is cold-swap; four-GPU support must be ordered at build time and cannot be retrofitted; and the four-GPU and NVMe options are mutually exclusive on the platform.

Our Assessment

Where it excels: the T640 8-Bay 3.5" is the right call when a deployment needs the flagship platform envelope (24 symmetric DIMMs, 3 TB memory, four GPUs, eight PCIe slots, NVDIMM-N) in a tower form factor with bulk LFF capacity as the storage priority. It is strong for branch-office virtualization hosts running 30 to 60 VMs with capacity-tier storage, remote-site SQL and Exchange servers with serious data sets, office-deployed GPU work (CAD, AI inference, dense VDI), and persistent-memory-aware workloads that need NVDIMM-N in a tower.

Where to look instead: if rack space is available and tower form factor is not required, the R740xd is the same platform in 2U and generally a better datacenter fit. If the workload fits a smaller envelope and budget is the constraint, the T440 is meaningfully cheaper and right-sized. If IOPS or NVMe matter more than bulk capacity, the T640 16-Bay 2.5" SFF configuration is the better choice on the same platform. All three are linked in the sections above and below.

Bottom line: this is the 14th gen tower to buy when you need flagship-tier platform headroom, want bulk LFF capacity, and require a tower form factor for office acoustics or sites with no rack. It is the last Dell tower built at the 24-DIMM, four-GPU, NVDIMM-N envelope, and there is no direct successor at that tier in 15th or 16th gen. If your deployment does not need the flagship envelope, we will tell you the T440 is the smarter buy; if you have rack space, we will point you to the R740xd. That is the call we make at quote time.

Where the T640 Fits in 2026

The T640 succeeds the 13th gen Dell PowerEdge T630 8-Bay 3.5" (13th gen flagship tower) (Broadwell, iDRAC8, 24 DIMMs at 2400 MT/s, two-GPU envelope, no NVMe). Moving up to the T640 brings the Skylake and Cascade Lake architecture, iDRAC9 with Silicon Root of Trust, faster memory at 2933 MT/s, four-GPU support, BOSS internal boot, and eight PCIe Gen3 slots. Buying a refurbished T630 in 2026 saves a little but gives up real platform value.

There is no direct flagship-tower successor in 15th or 16th gen. The 15th gen T550 tops out at 16 DDR DIMM slots (2 TB max) and two GPUs but brings PCIe Gen4 and 3rd Gen Xeon. The 16th gen Dell PowerEdge T560 12-Bay 3.5" (16th gen tower) moves to DDR5 at up to 4800 MT/s, PCIe Gen5, and BOSS-N1 NVMe boot, and supports up to six GPUs, but carries only 16 DDR5 DIMM slots (1 TB max) and no NVDIMM-N. For deployments that genuinely need 24 DIMMs, 3 TB of memory, or NVDIMM-N in a tower, the T640 is still the answer in 2026, and it is the last Dell tower built at that envelope. On support: Dell ProSupport for 14th gen is near end of extended support, so plan production coverage around third-party maintenance.

Honest Limitations

• PCIe Gen3 ceiling. No Gen4 or Gen5 expansion. Modern Gen4 NICs and HBAs run at roughly half native bandwidth; H100, L40S, and other Gen4/Gen5 GPUs are throttled by the bus. Match GPUs to the platform: V100, T4, A10, A30, A40, and A100 are well-suited; H100 and Gen5 cards are bottlenecked.
• No front NVMe on this chassis. The 8-Bay 3.5" backplane is SAS/SATA only. NVMe lives on the 16-Bay 2.5" configuration and specialist 24-Bay variants. For NVMe storage in a tower, choose the 16-Bay 2.5" or move to rack.
• Four GPUs and NVMe are mutually exclusive. Per Dell's platform spec, NVMe configurations cap GPUs at two. This LFF chassis supports the full four-GPU envelope precisely because it has no NVMe; if both matter, the platform forces a choice.
• Single-socket loses half the platform. Single-CPU T640 builds expose only 12 DIMMs and 3 PCIe slots. Single-socket is rarely the right call here; the T440 is better-positioned for single-socket tower needs.
• 2400W PSU derates at low line. Two-GPU-or-greater builds should run on 200 to 240V AC. At 100 to 120V AC the top PSUs derate and may force a lower-spec build.
• 5U footprint is large. Rack-converted, the T640 consumes 5U against the R740xd's 2U. For rack-dense sites the rack platforms are better-positioned; the tower makes sense for office and remote-site deployments.
• BOSS is cold-swap. Boot-module replacement needs downtime. Hot-swap boot arrived with 15th gen (BOSS-S2) and NVMe boot with 16th gen (BOSS-N1).
• iDRAC9 Express is insufficient for production. Always add Enterprise, especially at unattended sites. Remote console is the feature you miss most when something breaks with no on-site IT.
• NVDIMM-N has population rules. Persistent-memory builds need both CPUs, cannot mix NVDIMM-N with LRDIMM, and require OS support for storage-class memory (Windows Server 2016 and later with the right drivers, or Linux with libnvdimm). Confirm at deployment.
• Rack rails are a separate line item. The chassis is rack-convertible but the kit is not included. Add it to the BOM if rack deployment is planned.

Workload Fit

Where to Look Instead

If your deployment does not fit the T640 8-Bay 3.5", these are the configurations we point customers to:

• Dell PowerEdge R740xd 12-Bay 3.5" rack server: the same 14th gen platform in a 2U datacenter form factor with greater storage density and broader NVMe options. The better fit whenever rack space is available.
• Dell PowerEdge R650 8-Bay 2.5" (15th gen rack): a generation newer, with Ice Lake CPUs, DDR4 at 3200 MT/s, and PCIe Gen4, for deployments that want a current-tier rack platform rather than a 14th gen tower. For the SFF version of this T640 platform, the 16-Bay 2.5" configuration linked above is the companion to consider.

Ready to Configure?

Tell us your workload, target memory capacity, drive count and capacity per drive, single-socket or dual-socket, whether GPU acceleration is needed and how many cards, and whether NVDIMM-N persistent memory is in scope. We will translate that into a specific build and a firm quote.

Call 1-800-778-1545 or submit the quote form on this page and we will respond within 24 hours. Every T640 we ship is tested with a 12+ hour burn-in and backed by a 180-day warranty, with extended 1-Year, 2-Year, and 3-Year Premium coverage available. Volume pricing applies at 5 units and above.