Intel · Core X-Series
Intel Core i7-7740X X-series
High-frequency quad-core on X299 with dual-channel DDR4 and 16 CPU PCIe lanes.
Cores / Threads
4/ 8
Base / Boost
4.3/ 4.5 GHz
PCIe Lanes
16
TDP
112W
Memory
DDR4-2666Dual Channel
Socket
LGA2066
Verdict
7/ 10
A niche, high-clock quad-core for X299 that delivers strong single-threaded performance but lacks the PCIe and memory bandwidth of Skylake-X siblings, making sense only at low prices for specific reuse scenarios.
01 — Overview
What the Intel Core i7-7740X X-series is really about
The Intel Core i7-7740X is a quad-core, eight-thread desktop processor from the Kaby Lake-X family, designed for the LGA2066 (X299) platform with 14 nm manufacturing, a base clock of 4.30 GHz, and a max turbo of 4.50 GHz.
The Core i7-7740X combines 4 cores, 8 threads, 4.3–4.5 GHz clocks, and DDR4-2666 dual-channel memory on LGA2066, but only provides 16 PCIe lanes from the CPU and lacks integrated graphics, making it a specialized choice for existing X299 owners or overclockers.
High base and turbo clocks
4.30 GHz base and up to 4.50 GHz all-core Turbo Boost 2.0 frequency out of the box for strong single-thread performance.
Unlocked multiplier
Enables enthusiast overclocking on supported X299 boards with capable cooling and power delivery.
Dual-channel DDR4-2666
Supports up to 64 GB of DDR4-2666 memory with modest bandwidth compared to quad-channel HEDT CPUs.
16 CPU PCIe 3.0 lanes
Provides standard 1x16 or 2x8 configurations for GPUs, relying on chipset lanes for additional expansion.
02 — Specifications
Cross-referenced against the manufacturer's specification sheet and independent hardware reviews — no guesses.
03 — Performance
Real-world, not synthetic
How it actually performs where it matters — gaming, creation, virtualization, and efficiency.
Paired with a strong discrete GPU, the high clocks enable smooth high-refresh gaming, though newer platforms offer better efficiency and future-proofing.
Quad-core limits performance in heavily parallelized applications compared to higher core-count alternatives.
Adequate for light VM workloads, but limited core count and memory channels make it less suitable for heavy virtualization.
112 W TDP for a quad-core results in higher power draw per core than many modern designs.
Gaming Performance
Very Good- Strong single-threaded core performance keeps frame rates competitive in many titles
- Best paired with mid-to-high-end discrete GPUs
- Modern gaming CPUs with more cores and faster memory often deliver better 1% lows
04 — Architecture
Inside Intel Core X-series Processors
14 nm
Process Node
8 MB
L3 Smart Cache
4C / 8T
Core Configuration
Overview
Kaby Lake-X is a derivative of the mainstream Kaby Lake architecture adapted for the LGA2066 (X299) HEDT platform with four physical cores.
CPU Design
4 cores / 8 threads via Hyper-Threading, operating at high frequencies with an unlocked multiplier.
Memory Subsystem
Dual-channel DDR4 memory controller up to DDR4-2666, supporting up to 64 GB.
PCIe & I/O
16 PCIe 3.0 lanes directly from the CPU, plus additional lanes provided by the X299 chipset for expansion.
Overclocking
Unlocked multiplier designed for enthusiasts, supported by motherboards with robust VRM and cooling.
05 — Verdict
The good and the brutal
Strengths
High out-of-box clocks
Unlocked for overclocking
X299 platform offers flexible chipset PCIe lanes and storage options
Strong single-threaded performance for its era
Can breathe life into idle LGA2066 boards
Weaknesses
Quad core count limits multi-threaded performance
Only 16 CPU PCIe lanes
No integrated graphics
112 W TDP for four cores is relatively power-hungry
Platform is discontinued with limited future upgrade options
06 — History
Where it sits in the lineage
Predecessor
Intel Core i7-7700K (mainstream)
2017
Intel Core i7-7740X X-series
Successor
Platform superseded by Skylake-X and later HEDT/enthusiast lines
The Core i7-7740X arrived in 2017 as part of Intel’s X299 launch, blending a quad-core Kaby Lake-X die with the high-end desktop LGA2066 platform. It offered a familiar 4C/8T configuration at higher clocks, targeting enthusiasts who already invested in X299 boards and valued single-threaded performance. Unlike Skylake-X, Kaby Lake-X models retained dual-channel memory and 16 CPU PCIe lanes, which created clear segmentation within the X-series lineup.
Today it stands as a niche option for repurposing X299 systems on a tight budget.
Generation improvements
- Slightly higher base clock compared to i7-7700K
- Support for X299 platform and additional chipset PCIe lanes
- Higher overclocking headroom on many X299 boards
07 — Alternatives
What else should you consider?
AMD Ryzen 5 1600X
Gaming & Productivity
AMD Ryzen 7 1700
Creator
Intel Core i7-7700K
Gaming
Intel Core i5-7640X
Gaming
Intel Core i7-7820X
Workstation
Intel Core i7-8700K
AMD Ryzen 7 2700X
Intel Core i9-9900K
Intel Core i7-9700K
AMD Ryzen 5 3600
09 — Who's it for
Who should actually buy this
10 — Facts
Things you might not know
Kaby Lake-X quad-core models on LGA2066 use only two memory channels, unlike Skylake-X siblings which feature quad-channel memory.
Max memory bandwidth listed by Intel is 42 GB/s, consistent with dual-channel DDR4-2666 operation.
Intel ARK lists '0 QPI Links' and a Bus Speed of 8 GT/s for this processor.
The 8 MB Smart Cache size matches the mainstream i7-7700K, reflecting the shared lineage.
Intel ARK shows Intel Optane Memory Supported: Yes on this SKU.
Packaging thermal specification is PCG 2017X and TJUNCTION is 100°C.
Marketed as part of the X-series but with significantly fewer I/O resources than higher-end SKUs.
Boxed product does not include a stock cooler, requiring an aftermarket cooling solution.
Supports Intel VT-x and VT-d for virtualization.
End of Servicing Updates date on Intel ARK is March 31, 2024.
11 — PAA
People also ask
No, the i7-7740X does not include integrated graphics; a discrete GPU is required.
It uses the LGA2066 socket with the X299 chipset platform.
Yes, it features an unlocked multiplier for enthusiast overclocking.
It provides 16 PCIe 3.0 lanes from the CPU, configurable as 1x16 or 2x8.
It supports up to DDR4-2666 memory in dual-channel configuration up to 64 GB.
The processor has a 112 W TDP.
Only at very low prices to repurpose an existing X299 board; new builds should prefer newer platforms.
No, Kaby Lake-X supports dual-channel memory; quad-channel is exclusive to Skylake-X on X299.
Base clock is 4.30 GHz with a max turbo of 4.50 GHz.
No, the boxed product does not include a stock cooling solution.
12 — FAQ
Frequently asked questions
No, it supports DDR4 memory only.
Intel ARK lists ECC Memory Supported: No.
Up to 64 GB of DDR4-2666, dependent on the motherboard.
Intel ARK indicates Intel Optane Memory Supported: Yes.
14 nm.
8 MB Smart Cache.
Yes, Intel VT-x and Intel VT-d are supported.
Yes, it supports Intel SSE4.1, SSE4.2, and AVX2 extensions.
No, Intel lists Marketing Status: Discontinued.
100°C.