The HPE ProLiant ML350 Gen11 is a two-socket 4U tower server that takes up 5U of rack height once the tower-to-rack conversion kit is fitted. Two base chassis exist, and the real variety sits in the drive-cage kits, which stack into three boxes and cap the server at three cages in total. Accelerator support is where the tower pulls away from its 1U rack sibling: four full-height cards rather than a low-profile pair.
Cooling on this platform is the option group that connects everything else. There is no liquid cooling of any kind, and four separate air-cooling kits are selected by processor power, boot device, riser choice, memory density, drive class and accelerator simultaneously. A processor at or above 300 W, an EDSFF cage, a 256 GB DIMM or any accelerator each independently force the redundant fan kit, which in turn forces the second processor fan kit.
The ML350 Gen11 is a 4U tower that occupies 5U in a rack
HPE describes the ML350 Gen11 as a 4U tower with rack conversion capability, and states the consequence directly: when deployed as a rack model, this system will take up 5U of height in a standard data centre rack. The extra rack unit is the rail tray. There is exactly one conversion part, the ML Gen11 and Gen12 Tower to Rack Conversion Kit P47394-B21, which HPE describes as an easy-install rack rail tray taking up 1U of height in a standard rack.
Two things about that part change how it should be ordered. It includes the cable management arm and ships that way as standard, so there is no separate arm to buy and none to forget. And it is not a factory-integrable option: HPE states it can only be shipped with a standalone package, which means it arrives as its own carton rather than fitted to the server. A used ML350 Gen11 bought for a rack therefore needs the conversion kit confirmed as present, and a rack elevation drawn at 4U for it will be one unit short.
ML350 Gen11 chassis options and the three drive-cage boxes
Two CTO base chassis exist - the LFF server P48404-B21 with a 4 LFF SAS or SATA cage included, and the SFF server P48405-B21 with an 8 SFF SAS, SATA or x1 NVMe cage included - and both accept additional cage kits to a maximum of three cages. Mixed SFF and LFF cages are supported, and HPE states the practical rule for that case: a mixed build starts from the LFF server P48404-B21 as the base configuration, not from the SFF one.
| Drive-cage kit | Part | Reaches | Chassis rule |
|---|---|---|---|
| 8 SFF x1 U.3 Tri-Mode cage | P47217-B21 | Up to 24 SFF drives, as 8 plus 8 plus 8 | Stacks to three cages on either base |
| 4 LFF SAS or SATA basic cage | P47216-B21 | Up to 12 LFF drives, as 4 plus 4 plus 4 | Stacks to three cages on either base |
| 8 SFF x4 U.3 Tri-Mode cage | P47218-B21 | 8 SFF at x4 NVMe bandwidth | SFF base only; removes the default cage; no other cage may be selected; no field upgrade |
| 12 EDSFF cage | P48401-B21 | 12 EDSFF NVMe carriers | SFF base only; removes the default cage; no other cage; two processors required; 25 degrees C maximum inlet; no field upgrade |
Maximum internal storage follows the cage choice rather than the base server. Three 8 SFF cages reach 24 drives, which HPE quotes as 368.64 TB with SAS SSDs or the same figure with NVMe SSDs, and 57.6 TB with SAS hard drives. Three 4 LFF cages reach twelve drives at 312 TB with nearline SAS or SATA. The EDSFF cage holds twelve carriers at 183.6 TB. An internal LTO tape drive is supported to a maximum of one and occupies the Box 1 space, so a tape build gives up a drive cage position to get it.
The two FIO cages are the ones that close doors. Both the x4 NVMe cage and the EDSFF cage remove the default 8 SFF cage, forbid any other cage in the server, and carry no field upgrade path. Choosing either one means the server is a single-cage machine for the rest of its life, which on a tower bought to grow is a decision worth making deliberately rather than discovering later.
Processors, memory and the four fan kits that connect them
The ML350 Gen11 takes up to two Intel Xeon Scalable processors from the 4th or 5th generation, and HPE states that field upgrades from 4th generation to 5th generation parts are not supported. Eight processors on the list are single-socket parts and force a one-processor build - the 4th generation Gold 6438Y+, 6421N, 5411N and 6414U and Bronze 3408U, and the 5th generation Platinum 8581V and 8558U and Bronze 3508U. The Gold 6438Y+ is single-socket on this model but not on the rack siblings, which is the kind of per-model difference a shared parts list gets wrong. Both Bronze parts limit the platform to PCIe Gen4, and the Silver 4510, Silver 4509Y and Bronze 3508U do not support the Intel VROC NVMe feature at all.
Memory is 32 DIMM slots, sixteen per processor across eight channels at two DIMMs per channel, to a stated maximum of 8.0 TB. HPE attaches a condition to the slot count that the rack models do not carry: 32 DIMM slots require the selection of two processors. A single-processor ML350 Gen11 is a sixteen-slot server no matter which chassis it is built on. Quantity per socket must be 1, 2, 4, 6, 8, 12 or 16, and per-processor memory speed ceilings are explicit on this model - the Gold 6430 and 5418Y cap at 4400 MT/s, the Silver 4416+ and 4410Y at 4000 MT/s, the Platinum 8558 at 5200 MT/s - so the DIMM rating is not the binding number, the processor is.
| Cooling kit | Part | When HPE requires it |
|---|---|---|
| Standard heatsink | P47223-B21 | Processors below 195 W |
| Performance heatsink | P47224-B21 | Processors at or above 195 W |
| Second CPU fan kit | P47902-B21 | A second processor, a boot device, or the tertiary riser - it is the fourth fan |
| Redundant fan kit | P47219-B21 | Processors at or above 300 W, an EDSFF cage, SAS4 24G mixed-use SSDs, 256 GB memory, or any accelerator; forces the second CPU fan kit with it |
| External GPU fan kit | P47220-B21 | Required for the A16 and L4 accelerators; up to two kits |
A base ML350 Gen11 ships with three fans as standard and a second processor makes the fourth fan mandatory. Performance models ship with eight, which HPE says provides N+1 redundancy in most situations. High-density memory has a thermal price here as elsewhere: 256 GB memory is limited to a 25 degrees C maximum inlet temperature in a non-redundant fan configuration and 30 degrees C with the redundant fan kit fitted.
Storage controllers on the ML350 Gen11, and the 260 mm cable trap
The embedded Intel VROC SATA controller on an ML350 Gen11 covers more bays than its rack equivalents - up to twelve LFF drives as 4 plus 4 plus 4, or eight SFF - with each LFF cage forming a separate drive group and the SFF cage splitting into two groups across bays 1 to 4 and 5 to 8. Fitting the NS204i-u boot device reduces that: HPE states that when the boot device is selected, the embedded storage controller supports up to eight LFF as 4 plus 4, or 8 SFF. Beyond the embedded path, the controller list runs from the cacheless MR216i-o and MR216i-p through the 4 GB MR408i-o and MR408i-p and the 8 GB MR416i-o and MR416i-p to the SR932i-p, which handles up to 32 drives and requires a x16 riser to do it.
The trap on this model is cable length, and it is an expensive one to get wrong on a used purchase. The ML350 Gen11 uses 260 mm cache-backup parts - the 96 W lithium-ion battery P01367-B21, the hybrid capacitor P02381-B21 and the 16 W hybrid capacitor P65042-B21 - where the DL360 and DL380 rack models use the 145 mm parts P01366-B21, P02377-B21 and P65038-B21. The 145 mm parts can be used on an ML350 Gen11, but only with the additional Smart Storage Battery Cable Kit P58199-B21. A cached controller pulled from a rack ProLiant and dropped into a tower will arrive with a cable that does not reach.
Boot is the NS204i-u, P48183-B21, with 960 GB and self-encrypting 960 GB versions at P81160-B21 and P81162-B21. On this model it requires both the ML350 Gen11 NS204i-u Enablement Kit P48403-B21 and the second CPU fan kit. HPE also records an inlet limit worth knowing for a tower that may sit in an unconditioned room: with three drive cages fitted and no redundant fan kit, support is limited to a 25 degrees C maximum inlet temperature.
Expansion and accelerators: ten PCIe slots, and what a tower buys over a 1U rack
The ML350 Gen11 reaches ten PCIe Gen5 slots, which is more than any other Gen11 model in our catalogue, and six of those ten require the second processor. The default primary riser gives four x8 slots in x16 connectors, all full-height and full-length, from processor 1. The optional 2 x16 primary riser P48406-B21 replaces it and gives two true x16 slots in positions 2 and 4. The secondary riser is either four x8 slots at P48407-B21 or two x16 slots at P47238-B21, both from processor 2, and the tertiary riser P49693-B21 adds two half-height half-length x8 slots. HPE notes a legitimate single-processor use for the tertiary riser: without a second processor its slots have no function, but it still provides the power source for an internal LTO tape drive.
| Accelerator | Part | Maximum quantity | Requirement |
|---|---|---|---|
| NVIDIA L40 48 GB | S0K90C | 4 | x16 riser; one power cable kit P47221-B21 per card |
| NVIDIA A16 64 GB | R8T26C | 4 | External GPU fan kit P47220-B21; cable kit P39102-B21 covers up to three cards |
| NVIDIA L4 24 GB | S0K89C | 4 | External GPU fan kit P47220-B21 |
| NVIDIA L40S 48 GB | S2L70C | 2 | Slots 2 and 6 only, with the x16 riser cage; processor power at or below 190 W |
| NVIDIA RTX A1000 8 GB | S5T74C | 8 | Runs at x8, so no x16 riser is needed; up to eight across the 4x8 primary and secondary risers |
Four full-height accelerators is the number that separates this tower from the 1U rack ProLiant, which tops out at three low-profile cards. Every accelerator requires the redundant fan kit and the second CPU fan kit, mixing different accelerators is not supported, and any card needing x16 bandwidth requires either the 2 x16 primary riser or the 2 x16 secondary riser, each of which supports up to two such cards. The external GPU fan kit carries a physical consequence that catches people out: with it installed, the rear of the riser cage is covered and no external connectivity to the primary or secondary riser cage is allowed, which on the L40 and L40S also means the card's DisplayPorts cannot be connected.
Networking is a required selection rather than an assumption. There is no embedded network controller; HPE pre-selects a Broadcom BCM5719 1 Gb four-port BASE-T OCP3 adapter, P51181-B21, as the default. Two OCP slots exist - slot 14 as OCP 1 and slot 15 as OCP 2 - and Wake-on-LAN and shared-NIC behaviour are supported on slot 15 only, which requires the OCP2 enablement kit P47231-B21. An OCP-form RAID controller is supported on slot 14 only and does not need an enablement kit.
Power supplies on the ML350 Gen11
Power is HPE Flexible Slot, hot-plug, up to two supplies, and selecting two gives 1+1 redundancy. Mixing two different power supplies is not supported, so a redundant pair has to be two identical parts. The 500 W supply carries the tightest restriction on the list: HPE limits it to a single-processor configuration at 125 W of thermal design power, which rules it out of any dual-socket build.
| Power supply | Part | Efficiency grade | Constraint |
|---|---|---|---|
| 500 W Flex Slot | 865408-B21 | Platinum | Single 125 W processor configurations only |
| 800 W Flex Slot | P38995-B21 | Platinum | C-14 inlet |
| 1000 W Flex Slot | P03178-B21 | Titanium | C-14 inlet |
| 1600 W Flex Slot | P38997-B21 | Platinum | 200 to 240 VAC only |
| 1600 W Flex Slot DC | P17023-B21 | -48 VDC | Power lug kit P36877-B21 must be selected with it; supports 277 VAC and 380 VDC inputs |
| 1800 W to 2200 W Flex Slot | P44712-B21 | Titanium | 200 to 240 VAC only |
A six-foot IEC C-13 to C-14 jumper cord, A0K02A, ships with every pre-configured server and with each standard AC power supply option kit, so the rack-side cord is included rather than ordered. For a tower standing beside a desk rather than in a rack, the wall cord is the part that has to be specified for the region.
Managing an ML350 Gen11: iLO 6, physical security, and what does not transfer
Management is iLO 6 with Intelligent Provisioning and an HPE Compute Ops Management subscription included, with 64 MB of on-system flash behind it. Interfaces include a rear VGA port, a standard front DisplayPort, a 1 GbE dedicated iLO port, a front iLO Service Port, an optional rear serial port through cable kit P55062-B21, and five USB ports across the front, rear and interior.
Physical security is where a tower differs from a rack server, and the ML350 Gen11 treats it as standard equipment rather than an option. A front bezel key-lock feature is standard in both the tower and the rack model, and a padlock slot and a Kensington lock slot are both standard. That matters because a tower frequently lives in an office, a stockroom or a retail back room rather than behind a locked cage door. The only orderable security part is the ML Gen11 and Gen12 Intrusion Cable Kit P47226-B21. TPM 2.0 is listed as a standard security feature and no TPM module part number is offered, consistent with the rest of the Gen11 platform.
Entitlement is the part that does not follow used hardware. The included Compute Ops Management subscription is issued against the original order and dated from it, and iLO Advanced is a separately licensed tier. Neither can be confirmed by inspecting a chassis and neither is restored by a firmware reset, so both belong on the quote as line items rather than in the assumptions. HPE also documents a third service class on this model that the rack siblings do not spell out: non-CSR parts must be serviced by a trained authorised service engineer.
Where the ML350 Gen11 sits in the ProLiant lifecycle
The ML350 Gen11 is a CURRENT HPE product. Its QuickSpecs document identifier is a50004308enw and HPE last revised it at version 46 on 3 August 2026. Asking a supplier for that identifier by name is the reliable way to obtain the authoritative specification rather than a mirrored copy of an older revision, and every figure on this page can be checked against it.
Enterasource does not host, mirror or reproduce HPE QuickSpecs documents. HPE publishes no support-end date for the ML350 Gen11 on any public surface, so none appears here; the two lifecycle facts obtainable from a primary HPE source are the current status and the document revision.
ML350 Gen11 vs ML350 Gen10: what changed between the two tower generations
The step from ML350 Gen10 to ML350 Gen11 is a platform change rather than a refresh, and the two share little beyond the tower body and the 4U-to-5U rack behaviour. The Gen10 tower is an Intel Xeon Scalable 1st and 2nd generation machine with 24 DDR4 DIMM slots; the Gen11 is a 4th and 5th generation machine with 32 DDR5 slots and PCIe Gen5 throughout.
| Attribute | ML350 Gen11 | ML350 Gen10 |
|---|---|---|
| Processor platform | Intel Xeon Scalable, 4th and 5th generation | Intel Xeon Scalable, 1st and 2nd generation |
| DIMM slots | 32, DDR5, and 32 requires two processors | 24, DDR4, twelve per processor |
| Stated maximum memory | 8.0 TB | 3 TB with LRDIMM, 1.5 TB with RDIMM at 2933 MT/s |
| PCIe generation | Gen5, up to 10 slots | Gen3 |
| Drive cages | SFF, LFF, x4 NVMe and 12 EDSFF kits, up to three cages | SFF, LFF and LFF non-hot-plug cage kits |
| Form-Factor | 4U tower, 5U racked | 4U tower, 5U racked |
| Lifecycle status | CURRENT, doc a50004308enw v46 | RETIRED, doc a00021852enw v44 |
Choose the Gen11 when the workload needs DDR5 bandwidth, PCIe Gen5 devices or more than two accelerators. Choose the ML350 Gen10 when the requirement is a dependable dual-socket tower for file, print, directory, backup or a small virtualization estate, where DDR4 at 2933 MT/s is not the limiting factor and the platform's lower acquisition cost does the work. On the cross-brand side, the Dell tower of the Gen10 era is the PowerEdge T640; Dell has no 16th generation tower live in our catalogue to set against the Gen11.
Choosing within the Gen11 ProLiant line
The ML350 Gen11 is the tower member of the Gen11 line, and against its rack siblings the decision is about where the server has to live rather than what it has to do - the three share the same processor generations and the same 32-slot memory architecture.
| Model | Form-Factor | Front bay options | PCIe capacity | Where it fits |
|---|---|---|---|---|
| ML350 Gen11 | 4U tower, 5U racked, 2 sockets | SFF and LFF cage kits, up to three cages | Up to 10 slots | Offices, edge sites and rooms with no rack |
| DL380 Gen11 | 2U rack, 2 sockets | 8SFF, 24SFF, 8LFF, 12LFF, 12EDSFF | Up to 8 slots | The general-purpose dual-socket rack server |
| DL360 Gen11 | 1U rack, 2 sockets | 8SFF, 4LFF, 20EDSFF | Up to 3 slots | Density per rack unit |
| ML350 Gen10 | 4U tower, 5U racked, 2 sockets | SFF, LFF and LFF non-hot-plug cages | Gen3 slots | The value tower, two generations back |
For rack-mounted equivalents already live in our catalogue, the 2U DL380 Gen10 and the 1U DL360 Gen10 cover the same workloads in a rack, and the full Dell PowerEdge range covers the cross-brand alternatives.
Buying a refurbished ML350 Gen11
Three things decide whether a used ML350 Gen11 is the server you asked for. The first is the cage history: an x4 NVMe or EDSFF cage means the default 8 SFF cage was removed at the factory and no other cage can ever be added, so a single-cage machine is single-cage permanently. The second is the rack conversion kit, P47394-B21, which is not factory-integrable and therefore travels as a separate carton that a previous owner may not have kept. The third is the cache-backup cable: this tower uses 260 mm parts, and a controller transplanted from a rack ProLiant will have a 145 mm cable that needs kit P58199-B21 to work.
Enterasource builds each ML350 Gen11 to the specification ordered, whether it ships as a tower or with the rack conversion fitted. Every unit is tested on receipt, then disassembled, cleaned, inventoried, picked, assembled, configured and tested again on the bench before it leaves the building. Whole systems including this HP ProLiant server carry the 2-year Enterasource warranty, and shipping is free to the lower 48 states. Browse the full HPE ProLiant server range for the rest of the line.
Frequently Asked Questions
What are the HPE ProLiant ML350 Gen11 specifications?
Two sockets for 4th or 5th generation Intel Xeon Scalable processors, 32 DDR5 registered DIMM slots to a stated maximum of 8.0 TB with the second processor fitted, two base chassis in SFF and LFF form taking up to three drive cages, up to ten PCIe Gen5 slots of which six need the second processor, two OCP 3.0 slots, no embedded network controller, iLO 6 management with a Compute Ops Management subscription included, and up to two Flex Slot power supplies.
How much rack space does an ML350 Gen11 need?
Five rack units. The chassis itself is a 4U tower, and HPE states that when deployed as a rack model the system takes up 5U of height in a standard rack, because the tower-to-rack conversion kit P47394-B21 is a rail tray occupying 1U. That kit includes the cable management arm as standard and is not a factory-integrable option, so it ships as a standalone package rather than fitted to the server.
How many drives does an ML350 Gen11 hold?
Up to 24 small form-factor drives as three 8-bay cages, or up to 12 large form-factor drives as three 4-bay cages, or 12 EDSFF NVMe carriers with the dedicated EDSFF cage. HPE quotes 368.64 TB at the 24-drive SFF maximum with SAS or NVMe solid-state drives, 312 TB at the 12-drive LFF maximum with nearline drives, and 183.6 TB with the EDSFF cage. Mixed SFF and LFF cages are supported when the build starts from the LFF base server.
Does the ML350 Gen11 support GPUs?
Yes, and more of them than the rack siblings: up to four NVIDIA L40, A16 or L4 cards, up to two L40S cards restricted to slots 2 and 6 with a processor at or below 190 W, or up to eight RTX A1000 cards which run at x8 and need no x16 riser. Every accelerator requires the redundant fan kit and the second CPU fan kit, mixing different accelerator types is not supported, and x16 cards require a 2 x16 primary or secondary riser.
What changed between the ML350 Gen10 and the ML350 Gen11?
The platform changed rather than the body. The Gen10 tower runs Intel Xeon Scalable 1st and 2nd generation processors with 24 DDR4 DIMM slots and PCIe Gen3; the Gen11 runs 4th and 5th generation processors with 32 DDR5 slots, PCIe Gen5 and up to ten slots. Both are 4U towers that occupy 5U racked. The Gen10 QuickSpecs document a00021852enw is marked retired, while the Gen11 document a50004308enw remains current.
Where do I find the ML350 Gen11 QuickSpecs?
The document identifier is a50004308enw and the revision this page is written against is version 46, dated 3 August 2026. HPE publishes it directly, and quoting that identifier by name is the reliable route to the correct revision rather than a mirrored copy of an older one. Enterasource does not host or reproduce HPE QuickSpecs documents; every specification here is drawn from that identifier and can be verified against it.
