CPU Comparison
Core i7-3840QM vs Core i7-3940XM
A side-by-side comparison of specs, performance and value. The Intel Core i7-3840QM is a high-end mobile processor from the Ivy Bridge generation, designed to deliver robust performance for demanding laptop users. Released in September 2012, this quad-core CPU operates at a base frequency of 2.8 GHz and can boost up to 3.8 GHz using Intel's Turbo Boost technology. With eight threads thanks to Hyper-Threading, it handles multitasking and parallel workloads efficiently. The processor is built on a 22-nanometer manufacturing process, marking a significant shrink from the previous 32nm Sandy Bridge architecture. This allowed Intel to pack 1.4 billion transistors into a 160 mm² die while maintaining a reasonable 45-watt thermal design power. Featuring 8 MB of L3 cache, the i7-3840QM ensures quick data access for demanding applications. It also integrates Intel HD Graphics 4000, providing capable everyday graphics performance without needing a discrete GPU. This specific BGA variant is soldered directly to the motherboard, making it common in thinner, high-performance laptops of its era where upgradeability was sacrificed for compact form factors.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Still capable for basic office tasks and web browsing.
High clocks keep it surprisingly snappy for basic tasks.
Gaming
Handles older or lightweight games well but struggles with modern AAA titles.
Excellent for 2012 games, can still handle older esports titles.
Virtualization
VT-x support makes it suitable for light VMs on the go.
Great for running VMs on the go.
Efficiency
22nm was efficient for 2012, but modern 10nm/Intel 4 chips are far superior.
55W TDP is terrible for battery life.
Specialized Performance
AI / ML
- No AI acceleration hardware
- Too slow for modern AI workloads
- No modern AI support
- Instruction sets outdated
Content Creation
Gaming
- HD 4000 is not suitable for modern gaming
- Requires discrete GPU for AAA titles
- Fine for retro and indie games
- Max Ivy Bridge single-core speed
- Needs discrete GPU
- Overclockable for extra headroom
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Excellent performance for 2012 mobile
- 22nm process improved efficiency
- 8MB L3 cache
- Hyper-Threading support
Cons
- Soldered BGA package prevents upgrades
- Lacks AVX2 instruction set
- Weak integrated graphics by modern standards
- End-of-life with no security updates
Pros
- Unlocked multiplier for extreme overclocking
- Highest Ivy Bridge mobile clocks
- Socketed for upgrades
- Excellent 2012 performance
Cons
- Extremely high 55W TDP
- Runs very hot
- Lacks AVX2
- Massive power draw for mobile
Competitors & Alternatives
Core i7-3840QM
- AMD A10-4600MRival
Mobile
Newer Haswell architecture with better performance.
Compare head-to-headCheaper dual-core alternative from the same generation.
Compare head-to-head
Core i7-3940XM
- AMD A10-4600MRival
Mobile
- Intel Core i7-3920XMAlt
Slightly slower but essentially the same chip.
The newer Haswell-based Extreme Edition.
Compare head-to-head
Our Verdict on Each
For its time, the i7-3840QM was a mobile powerhouse offering excellent multi-threaded performance, though its soldered BGA package limits modern upgradeability.
Best for: Repairing an existing 2012-era premium laptop.
Read the full reviewA minor but potent refresh of the 3920XM, offering the absolute best Ivy Bridge mobile performance with unlocked overclocking potential.
Best for: Maxing out an old extreme gaming laptop.
Read the full reviewFrequently Asked Questions
Which is better, Core i7-3840QM or Core i7-3940XM?
Based on our editorial ratings, the Core i7-3940XM comes out ahead with a score of 8.2/10. That said, the best choice depends on your workload — check the spec and performance breakdown above for gaming, productivity and efficiency differences.
Which is faster for gaming, Core i7-3840QM or Core i7-3940XM?
For gaming, the Core i7-3940XM leads with a gaming performance score of 66/100 among Core i7-3840QM and Core i7-3940XM.
Which uses less power?
The Core i7-3840QM has the lowest rated TDP. Power draw across these chips: Core i7-3840QM (45 W), Core i7-3940XM (55 W).
Do Core i7-3840QM and Core i7-3940XM use the same socket?
No. They use different sockets (Core i7-3840QM: Intel BGA 1224, Core i7-3940XM: Intel Socket G2 (988B)), so each needs a compatible motherboard.
Which is faster in multi-core benchmarks?
The Core i7-3940XM posts the highest multi-core benchmark score. Multi-core results: Core i7-3840QM (8,100), Core i7-3940XM (9,200). Benchmark figures are approximate and workload-dependent.