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512MB DRAM module works perfectly as a spare for Cisco ISR 3925/3945, ensuring system reliability.
MEM-3900-512MB=
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512MB DRAM 1 DIMM FOR CISCO 3925/3945 ISR SPARE
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Name:
MEM-3900-512MB=
- Description:
- 512MB DRAM 1 DIMM FOR CISCO 3925/3945 ISR SPARE
- Rating:
Added to cart 28 times recently
- Availability:
In stock - Ready to Ship
- Brand:
- Cisco
- GTIN:
- 996280607551
- Condition:
- Warranty:
- 3
- List Price:
$575.00
- Price:
$210.0063.5% off
Quantity:
1
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MEM-3900-512MB= Overview
MEM-3900-512MB= is a DDR4 UDIMM module engineered for desktop, server, and laptop compatibility, operating at 3200 MHz with a CAS latency of CL16 and a voltage of 1.35V. This 512 GB memory module is delivered as a Single Channel kit, is non-ECC and unbuffered, and features an integrated heatspreader while not offering RGB lighting support.
Optimized for workstation builds and high-performance computing environments, this module meets rigorous speed and stability standards suitable for intensive gaming and professional tasks. Its design emphasizes thermal efficiency and reliability, ensuring consistent performance in demanding systems.
MEM-3900-512MB= price is $210.00, a 63.5% saving from the Cisco list price of $575.00. MEM-3900-512MB= is in stock and available for next-day dispatch. (terms applied)
Request bulk order quote for MEM-3900-512MB= for additional pricing. Browse the full 3900 Router Memory & Flash series or explore all Cisco products.
MEM-3900-512MB= Specifications
- Product Type
- Computer Memory
- Memory Type
- DDR4
- Capacity
- 512 GB
- Compatible Platforms
- Desktop / Laptop / Server
- Compatible Systems
- Workstation
- Form Factor
- UDIMM
- Kit Configuration
- Single Channel
- Speed
- 3200 MHz
- Operating Temperature
- N/A
- Reliability Rating
- Standard
- CAS Latency (CL)
- CL16
- Voltage
- 1.35V
- ECC Support
- No
- Registered/Buffered
- Unbuffered
- XMP Support
- Intel XMP 2.0
- RGB Lighting
- No
- Heatsink / Heatspreader
- Yes
- Intel Platform Support
- Intel 13th Gen
- AMD Platform Support
- AMD Ryzen 5000
- Use Case
- Workstation
- Product Name
- MEM-3900-512MB=
- Height
- 1.2 inches
- Width
- 5.3 inches
- Depth
- 0.6 inches
- Weight
- 0.3 lbs
MEM-3900-512MB= Use Case
VoIP and VPN Throughput Optimization in Enterprise Campus
In a large enterprise campus using Cisco 3925 ISR to terminate 250+ secure VPN tunnels and deliver QoS-driven VoIP, deploying the MEM-3900-512MB DRAM 1 DIMM FOR CISCO 3925/3945 ISR SPARE ensures sufficient packet buffering and routing-table capacity under peak loads. The result is a 30% reduction in jitter and packet loss during high-concurrency voice calls and encrypted data transfers, driving consistent user experience and SLA compliance.
Redundant Memory Provisioning for High Availability in Financial Services
A financial institution requires sub-minute failover on its Cisco 3945 ISR routers to maintain PCI and SOX compliance. Installing the MEM-3900-512MB DRAM 1 DIMM FOR CISCO 3925/3945 ISR SPARE as an on-site memory reserve enables immediate replacement in the event of DRAM failure, achieving a 99.99% network uptime. This rapid recovery strategy minimizes trading disruptions and protects critical transaction throughput.
Multi-Service Edge Routing and Virtualization in Distributed Retail Networks
A national retail chain consolidates branch services—firewall, WAN optimization, wireless LAN controller, and virtualization—on Cisco 3925 ISR platforms. Adding the MEM-3900-512MB DRAM 1 DIMM FOR CISCO 3925/3945 ISR SPARE expands memory headroom for multiple virtual contexts, enabling seamless service chaining and faster application deployment. The outcome is a 40% reduction in hardware footprint, lower CapEx, and accelerated time-to-market for new store services.
Quality Certifications
To get the detailed certification, please go to the Compliance Center.
Product Comparison Table 
| MEM-3900-512MB= |  MEM-3900-1GU4GB |  MEM-3900-1GB= |  MEM-3900-2GB= |  MEM-3900-1GU2GB | |
|---|---|---|---|---|---|
| AMD Platform Support | AMD Ryzen 5000 | N/A | AMD Ryzen 3000 | AMD Ryzen 3000 | N/A |
| CAS Latency (CL) | CL16 | CL16 | CL19 | CL16 | CL16 |
| Capacity | 512 GB | 4 GB | 1 GB | 2 GB | 4 GB |
| Compatible Platforms | Desktop / Laptop / Server | Desktop | Desktop | Desktop / Laptop / Server | Desktop / Laptop / Server |
| Compatible Systems | Workstation | N/A | N/A | N/A | N/A |
| Depth | 0.6 inches | 0.14 inches | 0.3 inches | 0.3 inches | 0.5 inches |
| ECC Support | No | No | No | No | No |
| Form Factor | UDIMM | UDIMM | UDIMM | UDIMM | UDIMM |
| Heatsink / Heatspreader | Yes | Yes | Yes | Yes | Yes |
| Height | 1.2 inches | 1.23 inches | 1.2 inches | 1.2 inches | 1.4 inches |
| Intel Platform Support | Intel 13th Gen | N/A | Intel 11th Gen | Intel Xeon E | N/A |
| Kit Configuration | Single Channel | Single Channel | Single Channel | Single Channel | Single Channel |
| Memory Type | DDR4 | DDR4 | DDR4 | DDR4 | DDR4 |
| Operating Temperature | N/A | N/A | N/A | N/A | N/A |
| Product Name | MEM-3900-512MB= | MEM-3900-1GU4GB | MEM-3900-1GB= | MEM-3900-2GB= | MEM-3900-1GU2GB |
| Product Type | Computer Memory | Computer Memory | Computer Memory | Computer Memory | Computer Memory |
| RGB Lighting | No | No | No | No | No |
| Registered/Buffered | Unbuffered | Unbuffered | Unbuffered | Unbuffered | Unbuffered |
| Reliability Rating | Standard | Standard | Standard | Standard | Standard |
| Speed | 3200 MHz | 3200 MHz | 3200 MHz | 2400 MHz | 3600 MHz |
| Use Case | Workstation | Gaming / Workstation | Workstation | General Use | General Use |
| Voltage | 1.35V | 1.35V | 1.35V | 1.2V | 1.35V |
| Weight | 0.3 lbs | 0.20 lbs | 0.2 lbs | 0.35 lbs | 0.25 lbs |
| Width | 5.3 inches | 5.25 inches | 5.3 inches | 5.3 inches | 5.3 inches |
| XMP Support | Intel XMP 2.0 | No | No | No | Intel XMP 2.0 |
Reviews & Ratings
F
Felix Bryant
4
Stable and easy-to-install memory solution.
G
Greta Lane
5
Professional-grade DRAM for ISR routers.
H
Hugo Carter
5
Maintains stable performance and reliability in critical applications.
I
Isabel Monroe
5
Simple upgrade with consistent results.
Questions & Answers
What is the MEM-3900-512MB= 512MB DRAM 1 DIMM for Cisco 3925/3945 ISR?
The MEM-3900-512MB= is a factory-tested 512 MB DRAM single-rank DIMM designed specifically as a spare or upgrade memory module for Cisco ISR 3925 and 3945 routers.
Is the MEM-3900-512MB= compatible with Cisco 3925 and 3945 routers?
Yes. The MEM-3900-512MB= meets Cisco’s form-factor, voltage, timing and density requirements for both ISR 3925 and 3945 models, ensuring full compatibility.
How do I install the 512MB DRAM DIMM in a Cisco 3925/3945?
Power down the router, open the chassis cover, align the DIMM with the slot keyed notch, firmly press until it clicks, then replace the cover and power up.
Will adding this 512MB DIMM improve my Cisco router’s performance?
Yes. Increasing DRAM capacity allows the router to handle more simultaneous sessions, larger routing tables and memory-intensive services, boosting overall throughput.
Can I mix the MEM-3900-512MB= with existing memory modules?
You can mix modules only if they share identical speed, density and voltage specifications. For best results, use matched pairs according to Cisco’s memory guidelines.
What are the technical specifications of the MEM-3900-512MB=?
This module is a 512 MB DDR2 SDRAM, single-rank, 240-pin DIMM, operating at 533 MHz (PC2-4200), 1.8 V, CL4 latency, fully tested for ISR 3925/3945 compatibility.
Is the MEM-3900-512MB= an original Cisco spare part?
Yes. It is an OEM spare part manufactured to Cisco’s quality standards and carries the Cisco part number MEM-3900-512MB=.
What warranty covers the MEM-3900-512MB=?
Cisco provides a one-year limited warranty for manufacturing defects. Extended support options are available through Cisco SMARTnet service.
How do I verify the authenticity of the MEM-3900-512MB=?
Check the Cisco logo, part number label, bar code and hologram on the packaging. Cross-reference with Cisco’s online product authenticity tool.
How long does shipping typically take for this DIMM?
Standard domestic shipping is 3–5 business days. Expedited and overnight shipping options are available at checkout.
What is the return policy for the MEM-3900-512MB=?
Unused modules in original packaging may be returned within 30 days for a full refund, subject to our standard return authorization process.
Does this memory module support all Cisco IOS features?
Yes. The additional DRAM capacity fully supports advanced Cisco IOS features such as VPN, MPLS, firewall and intrusion prevention.
How many memory DIMM slots are available on Cisco ISR 3925?
The Cisco ISR 3925 chassis includes two DIMM slots, allowing up to two 512 MB modules or a combination per Cisco memory guidelines.
Will installing the MEM-3900-512MB= affect power consumption?
Power draw increases marginally (approximately 1–2 W) per module. Ensure your power budget accounts for the additional memory load.
Can I upgrade both DIMM slots with MEM-3900-512MB=?
Yes. Installing two MEM-3900-512MB= modules populates both slots, doubling DRAM to 1 GB for maximum performance on ISR 3925/3945.
Where can I purchase the MEM-3900-512MB=?
You can order directly from Cisco’s online store, authorized partners or leading IT distributors. Check availability and pricing on Cisco.com.