815101-B21 is the HPE option part number for 64GB (1x64GB) Quad Rank x4 DDR4-2666 CAS-19-19-19 Load Reduced Smart Memory Kit. It is a single 64 GB DDR4 SDRAM LRDIMM in the 288-pin form factor, running at 2666 MHz to PC4-21300 with CAS latency CL19 and timings of 19-19-19 at 1.2 V. The module is quad rank with x4 chip organization, an 8192 x 72 configuration, load-reduced buffering and ECC for data integrity. It is listed for HPE Gen10 servers using first-generation processors, including the DL360 Gen10, DL380 Gen10, DL560 Gen10, DL580 Gen10, ML110 Gen10, ML350 Gen10, BL460c Gen10, XL170r Gen10 and XL190r Gen10.
HPE Option Part #: 815101-B21
HPE Spare Part #: 850882-001
HPE Assembly Part #: 840759-091
PRODUCT SPECIFICATIONS FOR 815101-B21:
- Type: DRAM
- Product Type: Memory module
- Form Factor: LRDIMM 288-pin
- Technology: DDR4 SDRAM
- Storage Capacity: 64 GB
- Registered or Buffered: Load-Reduced
- Data Integrity Check: ECC
- Module Configuration: 8192 x 72
- Chips Organization: X4
- Memory Speed: 2666 megahertz
- Memory Specification Compliance: PC4-21300
- Supply Voltage: 1.2 volt
- CAS Latency: CL19
- Latency Timings: 19-19-19
- RAM Features: Quad Rank
RESOURCES FOR 815101-B21
Quickspecs for 815101-B21COMPATIBLE WITH:
PROLIANT BL SERIES
PROLIANT DL SERIES
PROLIANT ML SERIES
PROLIANT XL SERIES
** This list may not be complete. Contact us via Live Chat if you have any questions about compatibility.
FREQUENTLY ASKED QUESTIONS ABOUT 815101-B21
What is the difference between 815101-B21 and 850882-001?
They are the same physical memory module under different HPE numbering schemes. This page, 815101-B21, is the option part number, the orderable kit number used when configuring or adding memory to a server. 850882-001 is the spare part number, used for service replacement of an installed module. This family also has one assembly revision, all shown in the cross-reference block on this page. An assembly part number identifies the manufactured build revision of the module itself rather than a sales or service kit.
What does this kit contain?
815101-B21 is a 1x64GB kit, so it supplies a single 64 GB LRDIMM rather than a matched multi-module set. The module is a 288-pin DDR4 LRDIMM with an 8192 x 72 module configuration and x4 chip organization. If you are populating multiple channels or filling a bank, plan the number of kits against the memory population rules for your specific server model.
Which servers accept this module?
The compatibility list covers HPE Gen10 platforms with first-generation processors: BL460c Gen10, DL360 Gen10, DL380 Gen10, DL560 Gen10, DL580 Gen10, ML110 Gen10, ML350 Gen10, XL170r Gen10 and XL190r Gen10. The first-generation CPU qualifier matters, because memory support differs by processor generation within the same server model. Confirm the installed processor generation before ordering.
Why is it load-reduced rather than registered?
This is a Load-Reduced DIMM, or LRDIMM. Load reduction buffers the data path in addition to the command and address lines, which reduces the electrical load a module places on the memory controller. That is what makes a quad rank, x4, 64 GB module practical at DDR4-2666 speeds. The module also includes ECC for data integrity check, as required on these server platforms.
What speed and latency does it run at?
The module is rated at 2666 MHz and complies with PC4-21300, with CAS latency CL19 and latency timings of 19-19-19 at a 1.2 V supply voltage. Actual operating speed is set by the server's memory controller and depends on the installed processor and the total DIMM population, so a fully populated configuration may clock below the module's rated 2666 MHz.
HPE PARTSURFER INFO FOR 815101-B21
| Spare PN | Description | |
|---|---|---|
 | 850882-001 | 64GB PC4-2666V-L, registered synchronous dynamic random access memory (SDRAM) 2Gx4, operated in a dual data rate (DDR4) mode, packaged in a dual in-line memory module (DIMM) organized as 8Gx72 |
Last Updated: 2026-09-26
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- Memory Capacity
- 64GB
- Memory Rank
- Quad Rank
- Memory Speed
- 2666 MHz
- Memory Type
- DDR4
7 Reviews
This product is warrantied against hardware failure for a period of 5 Years from the date of purchase. Before making a purchase, please take a moment to review our return policy below.
Returns
It is the customer's responsibility to verify compatibility with their machine(s) before placing an order. If an item is ordered by mistake, it can be returned for refund, minus a 25% restocking fee, within 5 business days of receipt. The cost of freight is not refundable.
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