United StatesName:
Added to cart 28 times recently
In stock - Ready to Ship
$1,204.00
$481.0060% off
Quantity:
Business price:
3 Year Extended Warranty
Same-day Shipping
14-Day Money Back Guarantee
Shipping:
Payment:
3 Year Extended Warranty
Same-day Shipping
14-Day Money Back Guarantee
Need Additional Discount on Product?
Request a quote below - Get Exclusive Pricing and Support.
Shipping:
Payment:
MEM-3900-1GU4GB
UPG 4GB FROM 1GB DRAM 2GB+2GB FOR 3925/3945 ISR
TRUSTED, TRIED, PROVEN
Inventory Delivered By
& Verified By
Solutions Powered By
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-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.
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.
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%.
To get the detailed certification, please go to the Compliance Center.
| 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 |
| Compatible Systems | N/A | N/A | N/A | N/A | Workstation |
| 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 |
| Operating Temperature | N/A | N/A | N/A | N/A | N/A |
| 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 |
| Intel Platform Support | N/A | N/A | Intel 11th Gen | Intel Xeon E | Intel 13th Gen |
| AMD Platform Support | N/A | N/A | AMD Ryzen 3000 | AMD Ryzen 3000 | AMD Ryzen 5000 |
| 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 |
Upgrading to 4GB DRAM on Cisco 3925/3945 improved performance and application responsiveness significantly.
Reliable memory upgrade that enhances system stability.
Simple to install and works flawlessly with ISR devices.
High-quality Cisco memory with consistent, dependable operation.
Boosts throughput and overall performance for demanding network tasks.
MEM-3900-1GU4GB is a Cisco-certified 4 GB DRAM upgrade kit (2×2 GB) designed specifically for Cisco ISR 3925 and 3945 routers.
Yes. MEM-3900-1GU4GB is engineered and tested for full compatibility with Cisco ISR 3925 and 3945 platforms to ensure reliable operation.
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.
Yes. Because the installation requires a power cycle, schedule a maintenance window to minimize network impact.
Upgrading to 4 GB DRAM enhances routing performance, enables larger routing tables, improves VPN throughput, and supports advanced services without memory constraints.
No. For optimal stability, install the MEM-3900-1GU4GB kit as a matched pair and remove any non-Cisco or mismatched DRAM modules.
Yes. The kit includes ECC-capable DRAM to detect and correct single-bit memory errors, ensuring data integrity and system reliability.
MEM-3900-1GU4GB carries a lifetime limited warranty backed by Cisco, covering defects in materials and workmanship under normal use.
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.
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.
No special tools are required. A standard Phillips screwdriver is sufficient to remove and replace the router’s chassis cover.
Standard delivery times vary by region but average 3–5 business days. Expedited options are available at checkout.
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.
No. MEM-3900-1GU4GB is specifically qualified for ISR 3925 and 3945. Using it in unsupported models may result in compatibility issues.
Yes. Cisco TAC provides 24×7 technical support for installation guidance, troubleshooting, and firmware compatibility questions.
Order directly from Cisco or an authorized Cisco partner. Verify the SKU label and Cisco hologram to confirm authenticity.
The kit includes a Quick Start Guide for installation steps and references to the Cisco ISR 3900 Series Hardware Installation Guide for detailed procedures.