Quick Verdict
A solid entry point into the HEDT market, offering 6 cores and DDR4 support, though aging rapidly compared to modern alternatives.
Overview
Launch
Sep 1st, 2014
Status
End-of-lifeGeneration
Core i7 (Haswell-E)
Market
Desktop
The Intel Core i7-5820K is a high-end desktop (HEDT) processor built on the Haswell-E architecture. Designed for enthusiasts and professionals, it features six cores and twelve threads, offering a significant multi-threaded performance leap over mainstream quad-core CPUs of its era. Operating at a base frequency of 3.3 GHz and boosting up to 3.6 GHz, it delivers robust computing power for demanding applications. Unlike mainstream chips, it utilizes the LGA 2011-v3 socket and the X99 chipset, supporting quad-channel DDR4 memory for massive memory bandwidth. With 28 PCIe 3.0 lanes, it provides extensive expansion capabilities for multi-GPU setups and high-speed storage arrays. The 140-watt TDP reflects its workstation-class design. While it lacks integrated graphics, requiring a discrete GPU, the 5820K excels in parallel processing tasks like video editing, 3D rendering, and virtualization, making it a powerhouse for creators who need more than standard desktop platforms offer.
The Intel Core i7-5820K is a Haswell-E processor with 6 cores and 12 threads. It features a base clock of 3.3 GHz and boosts up to 3.
6 GHz. With 28 PCIe lanes and quad-channel DDR4 support, it is designed for X99 workstations and creators needing high bandwidth.
Specifications
Performance
6 cores handle rendering well, but lack the speed of modern architectures.
Quad-channel memory and 12 threads make it great for VMs.
Good for gaming, but single-core speed lags behind modern CPUs.
140W TDP on 22nm is power-hungry by modern standards.
- •Can handle modern games with a discrete GPU
- •Lower single-core speed limits high-refresh gaming
- •Great for multi-tasking while gaming
- •No AI hardware
- •CPU inference is moderate due to core count
Architecture
22nm
Process Node
Haswell-E
Codename
6C / 12T
Core Config
15 MB
L3 Cache
140 W
TDP
Architecture Overview
Built on Intel's 22nm Haswell-E microarchitecture, the Core i7-5820K is designed for heavy multi-threaded workloads. It features a 6-core, 12-thread configuration utilizing Intel's Hyper-Threading technology. The architecture includes 15 MB of L3 SmartCache, ensuring efficient data sharing across the core complex. A defining feature of this HEDT platform is the quad-channel memory controller, supporting DDR4 up to 2133 MT/s, which provides massive memory bandwidth crucial for data-heavy applications. The processor offers 28 PCIe 3.0 lanes, a step down from the 40 lanes found on higher-end Haswell-E chips, but still sufficient for dual GPU configurations and multiple NVMe drives. The 140W TDP allows for aggressive turbo boosting and stable performance under sustained loads. The unlocked multiplier enables enthusiast overclocking, making it a favorite for users looking to push their X99 systems beyond stock specifications.
CPU Design
6 cores, 12 threads, unlocked.
Memory Subsystem
Quad-channel DDR4-2133.
PCIe & I/O
28 PCIe 3.0 lanes.
Overclocking
Fully unlocked multiplier.
- DDR4 memory support
- Haswell IPC improvements
- Better efficiency
Key Highlights
- 6 cores / 12 threads
- 28 PCIe lanes
- Quad-channel DDR4 memory
- Unlocked for overclocking
- High 140W TDP
- Older 22nm process
- Only 28 PCIe lanes
- Lacks integrated graphics
History
Released in September 2014, the Core i7-5820K was Intel's entry point into the Haswell-E HEDT lineup. It arrived as a more affordable alternative to the extreme editions, bringing 6-core performance to a wider audience of creators and enthusiasts. During this time, the PC landscape was shifting, with content creation becoming increasingly mainstream.
Users needed more cores for rendering and streaming, and the 5820K provided a cost-effective way to step up from quad-core mainstream processors. It succeeded the Ivy Bridge-E i7-4930K, offering DDR4 support and better efficiency. However, its release was somewhat overshadowed by the impending launch of AMD's Ryzen architecture, which would soon disrupt the HEDT market by offering more cores for less money.
Nevertheless, the 5820K served as a reliable workhorse for many professional builds, bridging the gap between mainstream and extreme computing.
Improvements over Previous Generation
- DDR4 memory support
- Haswell IPC improvements
- Better efficiency
Alternatives & Competitors
Should You Buy It?
Recommended for the right buyer
Upgrading an existing X99 system for more cores.
Avoid if…
- Building a new system
- Prioritizing single-core speed
- Need PCIe 4.0/5.0
Use Cases
Interesting Facts
Entry-level chip for the Haswell-E HEDT lineup.
Introduced DDR4 memory to the consumer market.
Has 28 PCIe lanes, compared to 40 on the 5930K.
Features a massive 356 mm² die.
Contains 2.6 billion transistors.
Uses the LGA 2011-v3 socket.
Launched in September 2014.
Requires a discrete GPU.
Has 15 MB of L3 cache.
Part number SR20S.
People Also Ask
Is the i7-5820K good for gaming?
It's okay for 60fps gaming, but its single-core speed is too slow for modern high-refresh titles.
Can the i7-5820K be overclocked?
Yes, it has an unlocked multiplier.
What socket does the i7-5820K use?
It uses the LGA 2011-v3 socket.
How many PCIe lanes does the i7-5820K have?
It has 28 PCIe 3.0 lanes.
Does the i7-5820K have integrated graphics?
No, it requires a discrete GPU.
What is the TDP of i7-5820K?
140 Watts.
How many cores does it have?
6 cores and 12 threads.
Does it support quad-channel memory?
Yes, it supports quad-channel DDR4.
Is it compatible with Windows 11?
Officially not supported, but runs perfectly fine.
What is the max turbo frequency?
3.6 GHz.
Frequently Asked Questions
Does the i7-5820K support Hyper-Threading?
Yes, 6 cores and 12 threads.
Does it support ECC memory?
No, ECC is not officially supported on this consumer HEDT chip.
What is the L3 cache size?
15 MB.
What chipset is required?
Intel X99.
Is it good for video editing?
Yes, 6 cores and quad-channel memory make it capable for 1080p and basic 4K editing.
Does it support Intel Optane?
No, Optane support started with 7th Gen.
What is the base clock?
3.3 GHz.
Does it support Turbo Boost Max 3.0?
No, that feature arrived with Broadwell-E.
Is it unlocked?
Yes.
Does it have vPro?
No, HEDT chips typically omit vPro.