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MEM-3900-1GU4GB
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Ready to Ship
UPG 4GB FROM 1GB DRAM 2GB+2GB FOR 3925/3945 ISR
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Hand-picked by our procurement team for standout value. This unit is offered at our sharpest price on current stock, verified against live market rates.
Name:
MEM-3900-1GU4GB
- Description:
- UPG 4GB FROM 1GB DRAM 2GB+2GB FOR 3925/3945 ISR
- Rating:
Added to cart 28 times recently
- Availability:
2 In stock - Ready to Ship
- Brand:
- Cisco
- GTIN:
- 0012306905293
- Condition:
Certified Refurbished
Professionally inspected, bench-tested, and firmware-verified, with configurations wiped. Restored to full working order and backed by our warranty.
- Warranty:
- 3
- List Price:
$1,204.00
- Price:
$481.0060% off
Quantity:
1
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MEM-3900-1GU4GB Overview
MEM-3900-1GU4GB is a high-performance DDR4 memory module engineered for desktop systems, offering a reliable and efficient solution for modern computing needs. It boasts a DIMM form factor with a speed of 3200 MHz, a CAS latency of CL16, and operates at a voltage of 1.35V, ensuring optimal performance for everyday computing tasks.
Designed with a 4 GB capacity in a single-channel kit configuration, MEM-3900-1GU4GB is non-ECC and unbuffered, making it perfectly suited for gaming and workstation builds. The module features an integrated heatspreader for better thermal management and does not incorporate RGB lighting, aligning with its focus on streamlined, high-quality performance.
MEM-3900-1GU4GB price is $481.00, a 60% saving from the Cisco list price of $1,204.00. MEM-3900-1GU4GB is in stock and available for next-day dispatch. (terms applied)
Request bulk order quote for MEM-3900-1GU4GB for additional pricing. Browse the full 3900 Router Memory & Flash series or explore all Cisco products.
MEM-3900-1GU4GB Specifications
- Product Type
- Computer Memory
- Brand
- Cisco
- Memory Type
- DDR4
- Capacity
- 4 GB
- Compatible Platforms
- Desktop
- Form Factor
- UDIMM
- Kit Configuration
- Single Channel
- Speed
- 3200 MHz
- Reliability Rating
- Standard
- CAS Latency (CL)
- CL16
- Voltage
- 1.35V
- ECC Support
- No
- Registered/Buffered
- Unbuffered
- XMP Support
- No
- RGB Lighting
- No
- Heatsink / Heatspreader
- Yes
- Use Case
- Gaming / Workstation
- Product Name
- MEM-3900-1GU4GB
- Height
- 1.23 inches
- Width
- 5.25 inches
- Depth
- 0.14 inches
- Weight
- 0.20 lbs
MEM-3900-1GU4GB Use Case
Accelerating Site-to-Site IPsec VPNs for Global Branch Networks
MEM-3900-1GU4GB-UPG DRAM upgrade powers Cisco ISR 3925/3945 routers at 150+ retail branches, boosting onboard memory from 1 GB to 4 GB. This upgrade supports 200 concurrent IPsec site-to-site VPN tunnels with AES-256 encryption and scalable route caching. Outcome: Sustains 200 Mbps encrypted throughput per branch, reduces latency by 30%, and ensures PCI DSS compliance.
Enhancing SD-WAN Edge Performance for Cloud Applications
MEM-3900-1GU4GB-UPG DRAM upgrade optimizes SD-WAN edge connectivity on Cisco ISR 3925/3945 routers for a professional services firm. The added 4 GB DRAM enables advanced dynamic path selection, real-time vAnalytics telemetry, and local internet breakout for Office 365 and Salesforce traffic. Outcome: Improves application response times by 40%, cuts WAN costs by 25%, and enforces SLA-driven QoS.
Enabling NFV and Multi-Service Virtualization at the Enterprise Edge
MEM-3900-1GU4GB-UPG DRAM upgrade unlocks NFV capabilities on Cisco ISR 3925/3945 edge platforms for a managed services provider. Expanding DRAM to 4 GB allows concurrent VNFs—firewall, WAN optimization, VoIP—on a single chassis while maintaining high throughput and low jitter. Outcome: Consolidates three standalone devices into one, reduces CapEx by 20%, and accelerates new service provisioning by 50%.
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Product Comparison Table 
| MEM-3900-1GU4GB |  MEM-3900-1GU2GB |  MEM-3900-1GB |  MEM-3900-2GB |  MEM-3900-512MB | |
|---|---|---|---|---|---|
| Product Type | Computer Memory | Computer Memory | Computer Memory | Computer Memory | Computer Memory |
| Memory Type | DDR4 | DDR4 | DDR4 | DDR4 | DDR4 |
| Capacity | 4 GB | 4 GB | 1 GB | 2 GB | 512 GB |
| Compatible Platforms | Desktop | Desktop / Laptop / Server | Desktop | Desktop / Laptop / Server | Desktop / Laptop / Server |
| Form Factor | UDIMM | UDIMM | UDIMM | UDIMM | UDIMM |
| Kit Configuration | Single Channel | Single Channel | Single Channel | Single Channel | Single Channel |
| Speed | 3200 MHz | 3600 MHz | 3200 MHz | 2400 MHz | 3200 MHz |
| Reliability Rating | Standard | Standard | Standard | Standard | Standard |
| CAS Latency (CL) | CL16 | CL16 | CL19 | CL16 | CL16 |
| Voltage | 1.35V | 1.35V | 1.35V | 1.2V | 1.35V |
| ECC Support | No | No | No | No | No |
| Registered/Buffered | Unbuffered | Unbuffered | Unbuffered | Unbuffered | Unbuffered |
| XMP Support | No | Intel XMP 2.0 | No | No | Intel XMP 2.0 |
| RGB Lighting | No | No | No | No | No |
| Heatsink / Heatspreader | Yes | Yes | Yes | Yes | Yes |
| Use Case | Gaming / Workstation | General Use | Workstation | General Use | Workstation |
| Product Name | MEM-3900-1GU4GB | MEM-3900-1GU2GB | MEM-3900-1GB | MEM-3900-2GB | MEM-3900-512MB |
| Height | 1.23 inches | 1.4 inches | 1.2 inches | 1.2 inches | 1.2 inches |
| Width | 5.25 inches | 5.3 inches | 5.3 inches | 5.3 inches | 5.3 inches |
| Depth | 0.14 inches | 0.5 inches | 0.3 inches | 0.3 inches | 0.6 inches |
| Weight | 0.20 lbs | 0.25 lbs | 0.2 lbs | 0.35 lbs | 0.3 lbs |
Compliance & Warranty
100% Genuine Product Guarantee
Every unit is authentic, sourced through trusted and authorised channels, and serial-verified on request. Genuine networking and IT hardware, guaranteed, or your money back.
Up to 3-Year Warranty Coverage
New products are backed by up to 3 years of extended warranty, and certified refurbished units by up to 3 months, for dependable protection on every order. Coverage is clear, honoured in full, and confirmed on each product page.
Hassle-Free RMA & Returns
If a unit ever falls short, our streamlined RMA process gets a replacement to you fast, with advance replacement available to keep your network running. No jargon, no runaround.
Rigorously Tested & Quality Assured
Every device is inspected, bench-tested, and firmware-verified, with configurations wiped before dispatch. Additional testing can be arranged to confirm full working condition on request.
Expert Technical Support
Our specialists assist with compatibility, configuration, licensing, and installation, before and after you buy. Real hardware expertise, whenever you need it.
Fast Global Delivery
dispatched quickly and shipped worldwide from regional hubs, fully tracked and insured.
Reviews & Ratings
K
Kieran Shaw
4
Upgrading to 4GB DRAM on Cisco 3925/3945 improved performance and application responsiveness significantly.
L
Lydia Fraser
5
Reliable memory upgrade that enhances system stability.
M
Marcus Price
5
Simple to install and works flawlessly with ISR devices.
N
Nina Ellis
5
High-quality Cisco memory with consistent, dependable operation.
O
Owen Tate
4
Boosts throughput and overall performance for demanding network tasks.
Questions & Answers
What is MEM-3900-1GU4GB?
MEM-3900-1GU4GB is a Cisco-certified 4 GB DRAM upgrade kit (2×2 GB) designed specifically for Cisco ISR 3925 and 3945 routers.
Is MEM-3900-1GU4GB compatible with Cisco ISR 3925 and 3945?
Yes. MEM-3900-1GU4GB is engineered and tested for full compatibility with Cisco ISR 3925 and 3945 platforms to ensure reliable operation.
How do I install MEM-3900-1GU4GB in my Cisco ISR router?
Power off the router, remove the chassis cover, align and insert the two 2 GB memory modules into the designated DRAM slots, replace the cover, and power on the device.
Do I need to schedule downtime for the memory upgrade?
Yes. Because the installation requires a power cycle, schedule a maintenance window to minimize network impact.
What performance benefits does the 4 GB upgrade provide?
Upgrading to 4 GB DRAM enhances routing performance, enables larger routing tables, improves VPN throughput, and supports advanced services without memory constraints.
Can I mix MEM-3900-1GU4GB modules with existing memory in my ISR?
No. For optimal stability, install the MEM-3900-1GU4GB kit as a matched pair and remove any non-Cisco or mismatched DRAM modules.
Does MEM-3900-1GU4GB support ECC (Error-Correcting Code)?
Yes. The kit includes ECC-capable DRAM to detect and correct single-bit memory errors, ensuring data integrity and system reliability.
What warranty covers MEM-3900-1GU4GB?
MEM-3900-1GU4GB carries a lifetime limited warranty backed by Cisco, covering defects in materials and workmanship under normal use.
How can I verify the memory upgrade after installation?
After reboot, log into the ISR CLI and run 'show platform hardware memory' or 'show version' to confirm the system recognizes the full 4 GB of DRAM.
What are the power and thermal requirements for MEM-3900-1GU4GB?
The upgrade operates within the existing power budget of Cisco ISR 3925/3945 and requires no additional cooling beyond the router’s standard airflow design.
Do I need special tools to install the MEM-3900-1GU4GB kit?
No special tools are required. A standard Phillips screwdriver is sufficient to remove and replace the router’s chassis cover.
How long does delivery of MEM-3900-1GU4GB typically take?
Standard delivery times vary by region but average 3–5 business days. Expedited options are available at checkout.
What is the return policy for MEM-3900-1GU4GB?
Unused and unopened modules can be returned within 30 days of receipt for a full refund, subject to Cisco’s return merchandise authorization (RMA) process.
Can I use MEM-3900-1GU4GB in other Cisco ISR models?
No. MEM-3900-1GU4GB is specifically qualified for ISR 3925 and 3945. Using it in unsupported models may result in compatibility issues.
Is technical support available for MEM-3900-1GU4GB installation?
Yes. Cisco TAC provides 24×7 technical support for installation guidance, troubleshooting, and firmware compatibility questions.
How do I ensure I’m purchasing authentic MEM-3900-1GU4GB modules?
Order directly from Cisco or an authorized Cisco partner. Verify the SKU label and Cisco hologram to confirm authenticity.
What documentation is provided with MEM-3900-1GU4GB?
The kit includes a Quick Start Guide for installation steps and references to the Cisco ISR 3900 Series Hardware Installation Guide for detailed procedures.