Quick Verdict
A highly efficient 9W processor that balances 10-core multitasking with extreme battery life, perfect for the most portable form factors.
Overview
Launch
2022
Status
ActiveGeneration
12th Gen
Market
Mobile
The Intel Core i5-1240U is an ultra-low power mobile processor from the 12th Generation Alder Lake-U lineup, released in February 2022.
The Intel Core i5-1240U leverages a 2 Performance-core and 8 Efficient-core design within a strict 9W base power envelope. This allows it to be used in fanless tablets and ultra-thin laptops. It features Iris Xe 80EU graphics and supports LPDDR5 memory, offering modern connectivity and processing capabilities for highly mobile users.
Specifications
Performance
Handles office tasks and browser tabs well, though burst limits are low.
Can run a light VM, but heavily constrained by the 9W power limit.
Only suitable for 2D or very old 3D games at low resolutions.
Exceptional efficiency, allowing for multi-day battery life in small batteries.
- •iGPU is capped at 900 MHz to save power.
- •Best for hardware video decoding and simple 2D games.
- •Not suitable for 3D gaming.
- •Handles basic background blur.
- •Not suited for any demanding AI workloads.
Architecture
10 nm
Process Node
Alder Lake-U
Codename
10C / 12T
Core Config
12 MB
L3 Cache
9 W
TDP
Architecture Overview
Built on the Intel 7 (10nm) process, the Core i5-1240U is designed to maximize performance per watt in the most constrained thermal environments.
CPU Design
Features 2 Golden Cove P-cores and 8 Gracemont E-cores, carefully binned to operate within a 9W base power envelope.
Memory Subsystem
Supports standard and low-power DDR4 and DDR5 modules to maximize battery life.
PCIe & I/O
Provides 14 PCIe 4.0 lanes for fast storage and connectivity in compact designs.
Overclocking
Fully locked multiplier for strict power management.
- Increased core count from 4 to 10.
- Better efficiency and battery life.
- Added DDR5 and PCIe 4.0 support.
Key Highlights
- Exceptional 9W power efficiency
- Allows for silent, fanless designs
- 10 cores for great everyday multitasking
- Supports LPDDR5 memory
- Excellent battery life
- Very low boost power limit (29W)
- iGPU clocked very low (900 MHz)
- Not suitable for heavy workloads
- Soldered to the motherboard
History
The introduction of the Core i5-1240U in early 2022 highlighted Intel's strategy to bring its hybrid architecture to the absolute lowest power tiers. Previously, Intel's Y-series processors operated at 5W and were essentially scaled-back U-series chips. With Alder Lake, Intel formalized a 9W base power target for ultra-portables, ensuring devices could remain fanless without sacrificing modern connectivity.
The i5-1240U emerged during a critical period where AMD was aggressively capturing the thin-and-light market. By offering 10 cores (2P+8E) in a 9W envelope, Intel provided a significant multi-threading advantage over traditional dual-core or quad-core low-power designs. The inclusion of DDR5 and LPDDR5 support also ensured that ultra-thin laptops could benefit from high memory bandwidth and lower power consumption.
The i5-1240U allowed manufacturers to create ultra-slim, highly responsive tablets and laptops that could handle modern workloads efficiently. This chip solidified the Alder Lake architecture's versatility, proving that the P-core and E-core combination was scalable from desktop replacements down to the most portable consumer electronics.
Improvements over Previous Generation
- Increased core count from 4 to 10.
- Better efficiency and battery life.
- Added DDR5 and PCIe 4.0 support.
Alternatives & Competitors
Should You Buy It?
Recommended for the right buyer
Buying an ultra-thin 2-in-1 convertible or a fanless tablet for note-taking and travel.
Avoid if…
- You need sustained performance for heavy workloads.
- You want to play games.
- You do software compilation.
Use Cases
Interesting Facts
The 1240U has a base TDP of just 9W, making it suitable for fanless tablets.
Despite 9W, it still manages 10 cores via the 2P+8E hybrid design.
The P-cores drop to a base clock of just 1.1 GHz to save power.
It uses a different socket (BGA 1781) than the 15W U and 28W P series.
The integrated graphics run at a max of 900 MHz, the lowest in the Alder Lake i5 mobile lineup.
It supports LPDDR4x and LPDDR5 for maximum space savings in ultra-thin chassis.
The chip can boost to 29W for short periods to handle sudden workload spikes.
Its E-cores can reach 3.3 GHz, matching the clock of the 15W 1235U's E-cores.
The 1240U was designed to compete directly with Apple's M-series chips in tablets.
It includes 12 MB of L3 cache, identical to the desktop-derived HX series.
People Also Ask
Is Intel Core i5-1240U good for gaming?
No, it is not suitable for gaming due to its 9W power limit and 900 MHz iGPU clock.
What is the TDP of the Core i5-1240U?
The base TDP is 9W, with a maximum turbo power of 29W.
How many cores does the i5-1240U have?
It has 10 cores: 2 Performance-cores and 8 Efficient-cores.
Does the i5-1240U support DDR5?
Yes, it supports DDR4, DDR5, LPDDR4x, and LPDDR5 memory.
Is the i5-1240U fanless?
It can be used in fanless designs due to its 9W TDP, but laptop manufacturers make the final cooling decision.
Can the i5-1240U be overclocked?
No, the multiplier is locked.
What socket does the i5-1240U use?
It uses the Intel BGA 1781 socket.
Does the i5-1240U have a built-in GPU?
Yes, it features Intel Iris Xe 80EU graphics capped at 900 MHz.
What generation is the Core i5-1240U?
It is a 12th Generation Intel Core processor.
Is the i5-1240U good for students?
Yes, its extreme efficiency makes it perfect for lightweight student tablets and laptops.
Frequently Asked Questions
Does the Core i5-1240U support hyper-threading?
Yes, the 2 P-cores support hyper-threading, combining with 8 E-cores for 12 total threads.
Can I upgrade the i5-1240U in my laptop?
No, it is soldered to the motherboard using the BGA 1781 socket.
What is the max turbo frequency of the i5-1240U?
The P-cores can boost up to 4.4 GHz.
Does the i5-1240U support PCIe 4.0?
Yes, it provides 14 PCIe 4.0 lanes for fast storage.
Is the i5-1240U better than the i5-1235U?
The 1235U is slightly faster due to a 15W TDP, but the 1240U is more efficient.
What cooling is required for the i5-1240U?
It can operate with a simple heatsink or passive cooling plate.
Does the i5-1240U support AVX2?
Yes, it supports AVX, AVX2, and FMA3 instructions.
What is the L3 cache size of the i5-1240U?
It has 12 MB of shared L3 cache.
Is the i5-1240U good for programming?
It is fine for basic web development, but not ideal for heavy compilation.
Does the i5-1240U support AV1 decoding?
Yes, the integrated Iris Xe graphics support hardware AV1 decoding.