HP 408855-S21 16GB Memory PC2-5300
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408855-S21 HP 16GB 667mhz Pc2-5300 Ecc Reg DDR2 SDRAM Dimm Bulk

Availability: In Stock
Part Number#: 408855-S21
List Price was: $47.49
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New Bulk Pack

Short Description:
408855-S21 16GB 2x8gb 667mhz Pc2-5300 Cl5 Ecc Registered Dual Rank DDR2 SDRAM Dimm 240-Pin Memory Module for Server | Made by HP | New Bulk Pack
Product Condition:
New Bulk Pack
Warranty provided by ALLHDD.COM:
90 Days

Introduction to the HP 16 GB DDR2 SDRAM Memory

Random Access Memory (RAM) is a vital component of any computing device. It is responsible for temporarily storing data and instructions that are required by the central processing unit (CPU) to execute tasks. When it comes to servers, which are responsible for serving multiple clients simultaneously, the amount and quality of RAM become even more important. In this article, we will explore in detail the specifications of the HP 408855-S21 16GB DDR2 SDRAM memory module designed for servers.

Product Specifications

The HP 408855-S21 is a DDR2 SDRAM memory module designed for servers. It is a dual-rank module, which means that it has two sets of memory chips that are accessed by the CPU separately. The memory module is registered, which means that it has an additional register between the memory module and the CPU, which helps to improve signal integrity and reduce electrical load. This makes registered memory modules more reliable and stable than unregistered ones. The HP 408855-S21 has a capacity of 16GB, which is the total amount of data that can be stored in it. It consists of 2 x 8GB memory chips, which are accessed separately by the CPU.

Clock Speed & Latency

The HP 408855-S21 has a clock speed of 667MHz. The clock speed determines the number of cycles per second at which the memory module can operate. A higher clock speed means that the memory module can process more data per second. However, the clock speed of the memory module must be compatible with the clock speed of the CPU and the motherboard. If the memory module has a higher clock speed than the CPU and the motherboard, it will not operate at its full potential. Therefore, it is essential to check the compatibility of the memory module with the CPU and the motherboard before installing it.

The HP 408855-S21 has a CAS latency of 5. The CAS latency determines the amount of time it takes for the memory module to respond to a request from the CPU. A lower CAS latency means that the memory module can respond faster to requests from the CPU. Therefore, a memory module with a lower CAS latency is better than one with a higher CAS latency. However, the CAS latency of the memory module must be compatible with the CPU and the motherboard. If the CAS latency of the memory module is not compatible with the CPU and the motherboard, it will not operate at its full potential.

Error Correcting Code (ECC)

The HP 408855-S21 has ECC support. ECC is a method of detecting and correcting errors in memory. It works by adding extra bits to the memory module, which are used to detect errors. If an error is detected, the ECC algorithm can correct it before the data is sent to the CPU. ECC memory is essential for servers because they are required to be highly reliable and stable. The ECC feature ensures that any errors in the memory module are detected and corrected before they cause any problems.

Memory Rank

The HP 408855-S21 is a dual-rank memory module. The rank of a memory module determines the number of banks of memory chips that are accessible by the CPU. A single-rank memory module has one bank of memory chips, while a dual-rank memory module has two banks of memory chips. The advantage of a dual-rank memory module is that it can provide better performance than a single-rank memory module. This is because the CPU can access two banks of memory chips simultaneously, which can improve the memory bandwidth.

DIMM Form Factor

The HP 408855-S21 is a DIMM (Dual In-Line Memory Module) form factor memory module. A DIMM is a type of memory module that has a printed circuit board with memory chips on both sides. DIMMs are commonly used in servers

Main Specification about the HP 408855-S21

  • Manufacturer: HP
  • Part Number or SKU# 408855-S21
  • Device Type: Memory (RAM
  • RAM Type: PC2-5300
  • Product Name: 16GB DDR2 SDRAM MEMORY Module

Technical Information

  • Storage Capacity: 16GB
  • Memory Technology: DDR2 SDRAM
  • Number Of Modules: 2 X 8GB
  • Memory Speed: 667mhz DDR2-667/PC2-5300
  • Data Integrity Check: Ecc
  • Signal Processing: Registered
  • Cas Latency Timings: Cl5
  • Platform Support: Proliant Server

Physical Characteristics

  • Dimensions (W X D X H) : 8.89 X 19.81 X 1.91 Cm (3.5 X 7.8 X 0.75 In)
  • Weight: 0.45 Kg (1 Lb)


  • HP Proliant Server Series
  • Dl785
  • Dl585
  • Dl385
  • Dl185
  • Dl180
  • Dl165
  • Bl685c
  • Bl465c
  • Bl2x220c
  • Bl260c
  • HP Proliant Blade Servers
  • Bl685c G6
  • Bl685c G5
  • Bl495c G6
  • Bl495c G5
  • Bl2x220c G5

Contact us or ask for live chat/help if you have any questions about the compatibility of this item to ensure the model's matching features with your current system.

About New Bulk Pack Products

New Bulk Pack products come with clamshell boxes and do not have any manufacturer warranty. Many times manufacturers disassemble whole units to use parts or pulled from a new system. Typically, this product doesn't come with software or instructions unless indicated and no Manufacturer’s genuine warranty. You can take note these are not brand new products.

PC2-5300 memory

Are you looking for the best PC-5300 modules for your server or PC? Allhdd.com is your one-stop-shop for modules from top brands on the market. We have a wide range of memory kits you can choose from. Browse through our website for the best PC2-5300 modules for all your needs.

Double Data Rate (DDR) stands for Synchronous Dynamic Random-Access Memory (SDRAM). It is the typical type of memory that serves as RAM for almost all modern-day processors.

The DDR2 SDRAM (Double Data Rate 2 SDRAM) is the upgrade to DDR SDRAM. It comes with a four-bit pre-fetch buffer and runs its external data bus at double the DDR SDRAM speed to facilitate a faster performance.

Buying DDR2 SDRAM from allhdd.com is pretty much straightforward if you know the front-bus of your system.

There are a handful of features to look out for when choosing a RAM. Suppose you wanted to decide between RAMs of varying clock speeds. In that case, the RAM with a greater clock speed is better. However, when choosing between RAMs of identical clock speeds, the RAM with lower CAS latency will perform faster. Latency is a measure of how long it takes to collect data from memory. The higher this figure, the greater the latency.

The DDR2 PC2-5300 memory is generally regarded as DDR2-667. Its design and unique features work efficiently with systems featuring a 333MHz front-side bus, rendering a data transfer rate of 667MT/s.

The PC2 5300 RAM has a module bandwidth of 5300MB/s. This bandwidth is the highest amount of data the PC2 5300 transfers every second.

Depending on your preference and budget, there are various PC2-5300 memory kits and sizes you can buy here on allhdd.com. These include 4GB, 8GB, 16GB, 64GB, 32GB, and 128GB memory kits. All units are brand new and available at pocket-friendly prices.

Factors to consider before buying the PC2 modules

Your system's RAM is the single most crucial feature for a flawless performance. Hence, picking one requires some attention to certain factors.

  1. Frequency

You should know the frequency at which your server or computer motherboard operates. It is catastrophic to mount a memory with a lower frequency than the motherboard's minimum frequency. You risk damaging both RAM and your motherboard. Here are the typical speeds for DDR2 SDRAM modules:

PC2-6400 (DDR2-800)

PC2-3200 (DDR2-400 at 3200Mbps throughput)

PC2-8500 (DDR2-1066), and

PC2-5300 (DDR2-667).

  1. RAM Size

Depending on your hardware, the modern-day memory module size ranges from 4GB to 128GB. If your system performs a lot of multitasking daily, you'll need a bigger RAM size. You can buy all memory kits ranging from 4GB, 8GB, 16GB, 64GB, 32GB, and 128GB, 256GB, 512GB, 1TB, and more here on allhdd.com.

  1. DDR Generation

Motherboards that are built to support the newer generation DDR will not work with older generations. Be sure to figure out what works for your PC. A DDR2 memory module will not work on a motherboard that features a DDR3 DIMM slot. The same thing applies to other memory modules and DIMM slots.

  1. Number of Channels

Dual channels are the most preferred choice when it comes to the channel number. Say your PC needs 16GB; in that case, you can take a two 8GB memory kit in dual channel mode.

Allhdd.com offers all the top-range memory modules from well-known brands. You get to save more when you shop on allhdd.com. Enjoy free Ground Shipping on all orders placed within all states in the US. Rest easy; there is expert advice and an information support desk if you get stuck.


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Replacement or refund. In the case of material defects, we will try to replace the product first. The product will be replaced before the expiration of the original warranty. For any failure of hardware, if we cannot process the replacement of the product(s)/model(s), we will refund the original selling/invoiced price. The shipping costs and sales tax, if any, are non-refundable. ALLHDD retains the right to decide whether the item(s) will process for replacement or refund.

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In general, a manufacturer's warranty service/support is a written guarantee to the buyer of a product. Its terms assure the replacement or repair of the product, if necessary, within a specified period after the purchase (2-5 years depending on the brand/manufacturer). It is typically included in the price of the product. Products are brand new and sealed and the original manufacturer box is complete with the Manufacturer's genuine warranty. For most of the brand new/retail products that come with the manual and box, exceptions may apply (i.e., Cisco, Juniper Networks).

For the server parts (i.e., Dell, HPE) to get Full coverage of the warranty server must have a full 3- 5 years warranty. However, ALLHDD.COM will cover the warranty duration if any Manufacturer doesn't support the advertised warranty and there is no refund for those.
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