Intel SR3B3 Xeon Gold 6126 12-Core 2.6GHz Server CPU (Renewed)

Name: Intel SR3B3 Xeon Gold 6126 12-Core 2.6GHz Server CPU (Renewed)
Brand: Intel
SKU: SR3B3

Overview

The Intel Xeon Gold 6126 SR3B3 is a 12-core, 24-thread Skylake-SP processor in the LGA 3647 socket, operating at 2.6GHz base with a single-core Turbo peak of 3.7GHz and a 125W TDP. The 19.25MB L3 cache is the architectural detail that most directly affects day-to-day server performance — large working sets in database query engines, ERP systems, and virtualization overhead can often be served from cache rather than triggering full DRAM latency cycles, which compounds across hundreds of concurrent threads in a busy server. The 6-channel DDR4-2666 memory controller delivers up to 119.2 GB/s of theoretical bandwidth per socket, meaning a dual-socket board with two Gold 6126s can sustain combined memory throughput that most storage and network fabrics cannot saturate. AVX-512 support is present, though buyers should account for the Skylake-SP behavior of frequency reduction when AVX-512 code paths are active under sustained load.

The Gold 6126 sits in a cost-effective tier of the Xeon Gold lineup — positioned above the 8-core Silver class in core count and cache, but below the Gold 6148 and 6154 in per-core frequency and total cache. It's the right fit for dual-socket server upgrades in HP ProLiant Gen10, Dell PowerEdge R7xx, or SuperMicro X11 platforms where the goal is maximizing thread count per watt and cache depth for mixed virtualization or HPC workloads. The renewed designation makes this a logical choice for secondary compute nodes, lab infrastructure, or budget-sensitive deployments where Cascade Lake or Ice Lake pricing is prohibitive. A firmware and microcode verification pass on the target platform before deployment is standard practice, as is confirming that both sockets in a dual-socket build carry the same SR3B3 stepping for interoperability.

Key Features

Intel Xeon Processor Gold 6126 SR3B3

L3 Cache: 19.25MB

2.6GHz

12-Core

Specifications

Brand

Intel

Model

Xeon Gold 6126 SR3B3

Core Count

12 cores / 24 threads

Base Clock

2.6GHz

Max Turbo Boost

3.7GHz (single-core)

L3 Cache

19.25MB

TDP

125W

Socket

LGA 3647

Memory Channels

6-channel DDR4-2666

Max Memory Bandwidth

119.2 GB/s (per socket)

Instruction Sets

AVX-512, SSE4.2, AES-NI

Condition

Renewed

Similar Products

Other products from the same family that visitors often consider:

✓ Available

Pros & Cons

👍 Pros

12 cores and 24 threads at up to 3.7GHz single-core Turbo on the Gold 6126 provide strong parallel throughput combined with respectable single-threaded headroom for mixed server workloads.
19.25MB L3 cache reduces main memory access latency for working datasets that fit within cache, benefiting database query engines, in-memory analytics, and compiler toolchains.
6-channel DDR4-2666 memory controller per socket delivers up to 119.2 GB/s bandwidth — the bottleneck for memory-bound workloads moves to storage or network rather than the CPU-to-RAM bus.
LGA 3647 UPI interconnect supports native dual-socket coherent operation at 10.4 GT/s, enabling 24-core configurations without a separate chipset or fabric.
Renewed pricing provides access to Gold-tier Xeon performance — with AVX-512 support — at a significant discount versus new Skylake-SP silicon.

👎 Cons

125W TDP requires platform-specific LGA 3647 active cooling; this CPU cannot be installed without a compatible server heatsink or chassis airflow solution, adding procurement complexity if upgrading outside of a complete server system.
The Skylake-SP generation does not support PCIe 4.0 — platform I/O bandwidth is capped at PCIe 3.0 speeds, which can be a bottleneck for high-throughput NVMe storage arrays or GPU compute workloads that saturate PCIe 3.0 x16.
As a renewed unit, thermal interface material (TIM) on the IHS may have degraded from the original application; a repaste is advisable before deploying in a thermally sensitive or sustained-load environment.
DDR4-2666 maximum memory speed is below the DDR4-3200 ceiling of newer Ice Lake-SP and Sapphire Rapids Xeons, limiting memory bandwidth for workloads that are sensitive to that metric.
AVX-512 execution under sustained workloads causes frequency reduction on Skylake-SP — applications that heavily leverage AVX-512 will see clock speeds drop below the rated Turbo ceiling while under that instruction width.

Frequently Asked Questions

What platform does the Xeon Gold 6126 SR3B3 require, and is it compatible with first-gen Skylake-SP boards?

The Gold 6126 uses the LGA 3647 socket and requires a Skylake-SP (Purley) platform motherboard — including HP Z8 G4, Dell PowerEdge R640/R740, and SuperMicro X11 boards. It is not compatible with Ice Lake-SP (LGA 4189) or Cascade Lake platforms without explicit cross-generation board support from the manufacturer.

What is the maximum Turbo Boost frequency on the 6126, and does all-core Turbo differ from single-core?

The Gold 6126 boosts to 3.7GHz on a single core under Intel Turbo Boost 2.0. All-core Turbo under full 12-core load steps down, typically sustaining in the 3.0–3.2GHz range depending on thermal headroom and platform power limits — an important distinction for workloads that parallelize fully versus those with a critical serial path.

How many memory channels and what maximum RAM does the 6126 support per socket?

The Xeon Gold 6126 supports 6-channel DDR4 memory per socket, with a maximum of 768GB per CPU using 128GB LRDIMMs. The 6-channel configuration delivers up to 119.2 GB/s theoretical memory bandwidth at DDR4-2666 speed — a significant advantage over the 4-channel platforms used in desktop and workstation Xeons.

Is the 6126 SR3B3 suitable for a dual-socket configuration?

Yes. The Gold 6126 fully supports dual-socket UPI interconnects via Intel's Ultra Path Interconnect at up to 10.4 GT/s per link. In a dual-socket system you get 24 physical cores and 48 threads with coherent shared memory access across both sockets — the SR3B3 designation is the specific stepping identifier, and both sockets must use the same stepping for guaranteed compatibility.

What TDP does this processor carry, and what cooling requirement does that create?

The Gold 6126 is rated at 125W TDP. Server platforms using this CPU require active cooling — either vendor-approved heatsinks (HP, Dell, SuperMicro all specify approved airflow and heatsink SKUs) or in a rack server, the chassis' redundant fans provide the required airflow. Desktop CPU coolers are not compatible with LGA 3647 without an adapter bracket, and are generally not recommended for sustained server workloads.