Intel Core i7-3840QM vs Intel Xeon E3-1220 v5 Comparison

The Intel Core i7-3840QM is the faster chip in every measured benchmark, but the Intel Xeon E3-1220 v5 is the only one with server-grade features. The i7-3840QM wins all six head-to-head Cinebench tests, with margins ranging from 2% to 2.9%, and it does so while drawing 35W less power. However, the Xeon E3-1220 v5 is the sole option for users who need ECC memory support or a socketed desktop platform. The data shows the i7-3840QM is the performance pick for mobile or embedded work, while the Xeon E3-1220 v5 is the workstation-oriented choice with validation for reliability-critical tasks.

The Verdict

The Intel Core i7-3840QM is the clear winner on raw benchmark performance. It beats the Xeon E3-1220 v5 in every single head-to-head test: Cinebench R15 multicore (498 vs 488, a 2% lead), R15 singlecore (70 vs 68, a 2.9% lead), R20 multicore (2079 vs 2034, a 2.2% lead), R20 singlecore (293 vs 287, a 2% lead), R23 multicore (4952 vs 4845, a 2.2% lead), and R23 singlecore (699 vs 684, a 2.1% lead). This consistency is notable because the two chips share the same core count (4 cores) and identical L3 cache size (8 MB shared), yet the i7-3840QM’s 8 threads versus the Xeon’s 4 threads give it the edge in multithreaded workloads. The i7-3840QM also achieves this with a 45W TDP compared to the Xeon’s 80W, making it the more efficient choice per watt.

The Xeon E3-1220 v5, however, is not without purpose. Its launch MSRP is $203, and it supports ECC memory, which the i7-3840QM does not. It also uses the Intel Socket 1151 platform, meaning it can be dropped into a desktop motherboard, whereas the i7-3840QM is soldered to Intel BGA 1224 and is therefore limited to mobile or embedded systems. The Xeon also supports both DDR3 and DDR4 memory, while the i7-3840QM is limited to DDR3. For anyone building a compact server or a workstation where data integrity matters more than a 2% performance delta, the Xeon is the rational pick. For everyone else, the i7-3840QM’s benchmark dominance makes it the better processor.

FAQ

Q: Which CPU has higher single-core performance?

A: The Intel Core i7-3840QM wins every single-core test. It leads by 2.9% in Cinebench R15 singlecore (70 vs 68), 2% in R20 singlecore (293 vs 287), and 2.1% in R23 singlecore (699 vs 684).

Q: Does the Xeon E3-1220 v5 support ECC memory?

A: Yes. The Xeon E3-1220 v5 has ECC memory support set to true, while the Intel Core i7-3840QM does not support ECC memory.

Q: What is the difference in power consumption?

A: The Intel Core i7-3840QM has a TDP of 45W, while the Intel Xeon E3-1220 v5 has a TDP of 80W. This means the i7-3840QM draws 35W less power.

Q: Which processor has more threads?

A: The Intel Core i7-3840QM has 8 threads, while the Intel Xeon E3-1220 v5 has 4 threads. Both have 4 physical cores.

Q: Are these processors on the same socket?

A: No. The Xeon E3-1220 v5 uses Intel Socket 1151, while the Core i7-3840QM uses Intel BGA 1224.

Q: Which chip has a higher average benchmark score?

A: The Intel Core i7-3840QM has an average benchmark score of 1416, while the Intel Xeon E3-1220 v5 has an average score of 1401. The i7-3840QM is also ranked 37th percentile versus all CPUs, same as the Xeon.

Architecture Differences

The two processors come from different Intel generations and process nodes. The Xeon E3-1220 v5 is built on Skylake-DT architecture using a 14 nm process, while the Core i7-3840QM uses the older Ivy Bridge architecture on a 22 nm process. This node difference is significant: the Xeon packs 1,750 million transistors into a 122 mm² die, whereas the i7-3840QM has 1,400 million transistors on a larger 160 mm² die. The smaller, denser Skylake die is a key reason the Xeon achieves a lower TDP per core, though the i7-3840QM’s overall TDP is still lower at 45W versus 80W.

Both chips have 4 cores and identical cache hierarchies: 64 KB L1 per core, 256 KB L2 per core, and 8 MB shared L3. The critical architectural difference is threading. The i7-3840QM supports 8 threads via Hyper-Threading, while the Xeon E3-1220 v5 is limited to 4 threads. This explains the i7-3840QM’s consistent lead in multithreaded Cinebench tests despite its older architecture. The i7-3840QM also integrates Intel HD 4000 graphics, while the Xeon has no integrated graphics at all, meaning the Xeon requires a discrete GPU for display output.

Memory support diverges sharply. The Xeon supports both DDR3 and DDR4 with dual-channel memory bus and a memory bandwidth of 34.1 GB/s, plus ECC memory for error correction. The i7-3840QM only supports DDR3, also dual-channel, with no listed memory bandwidth and no ECC capability. The Xeon also has PCIe Gen 3 with 16 lanes (CPU only), while the i7-3840QM has no PCIe specification listed. For a server or workstation, the Xeon’s ECC and broader memory options are decisive; for a mobile chip, the i7-3840QM’s integrated graphics are a practical necessity.

Specification Differences

The most consequential differences are in threading, power, socket, and memory support. The Xeon E3-1220 v5 has 4 cores and 4 threads, while the Core i7-3840QM has 4 cores and 8 threads. Base clocks are close: 3.00 GHz for the Xeon versus 2.80 GHz for the i7-3840QM, but the i7-3840QM boosts higher at 3.80 GHz versus the Xeon’s 3.50 GHz. TDP differs by 35W, with the Xeon at 80W and the i7-3840QM at 45W.

The sockets are incompatible: the Xeon uses Intel Socket 1151, while the i7-3840QM uses Intel BGA 1224 (soldered). Process node differs (14 nm vs 22 nm), as do transistor counts (1,750 million vs 1,400 million) and die size (122 mm² vs 160 mm²). Memory support is a major split: the Xeon supports DDR3 and DDR4 with ECC, while the i7-3840QM only supports DDR3 without ECC. The Xeon has a listed memory bandwidth of 34.1 GB/s; the i7-3840QM has no bandwidth figure. The Xeon has PCIe Gen 3 with 16 lanes; the i7-3840QM has no PCIe data. The Xeon has no integrated graphics, while the i7-3840QM includes Intel HD 4000. The Xeon’s launch MSRP is $203; the i7-3840QM has no launch MSRP listed.

Head-to-Head Benchmarks

The data is unambiguous: the Intel Core i7-3840QM wins all six head-to-head Cinebench tests, but the margins are narrow. In Cinebench R15 multicore, the i7-3840QM scores 498 against the Xeon’s 488, a 2% advantage. In R15 singlecore, the lead grows to 2.9% (70 vs 68). The R20 tests show a 2.2% multicore lead (2079 vs 2034) and a 2% singlecore lead (293 vs 287). The R23 tests mirror this: 2.2% multicore (4952 vs 4845) and 2.1% singlecore (699 vs 684).

The consistency of these results is noteworthy. The i7-3840QM’s advantage is not workload-specific; it holds across every rendering test, from the older R15 to the newer R23. The single-core wins are particularly telling because they cannot be attributed to the i7-3840QM’s extra threads. The i7-3840QM’s higher boost clock of 3.80 GHz versus the Xeon’s 3.50 GHz likely drives these single-core victories. The multicore wins are likely driven by the i7-3840QM’s 8 threads versus the Xeon’s 4 threads, despite the Xeon’s higher base clock.

The average benchmark scores reinforce this picture. The i7-3840QM averages 1416, while the Xeon averages 1401. Both sit at the 37th percentile of all CPUs. The nearest rivals for the i7-3840QM include the AMD Ryzen 7 2700U (avg 1415, delta 0.1%) and Intel Core i5-4460 (avg 1415, delta 0.1%), which shows the i7-3840QM is performing at the level of much newer mainstream chips. The Xeon’s nearest rival is the Intel Xeon E-2104G (avg 1402, delta 0%), indicating it is essentially tied with a newer entry-level Xeon.

Where Each One Wins

The Intel Core i7-3840QM wins in every performance category measured. It is the faster chip for single-threaded tasks like older games or lightly threaded applications, as shown by its 2.9% lead in R15 singlecore. It is also faster for multithreaded rendering workloads, as demonstrated by its 2.2% lead in R23 multicore. Its 45W TDP makes it a better fit for laptops, all-in-ones, or any power-constrained environment. The inclusion of Intel HD 4000 graphics also means the i7-3840QM can run a display without a discrete GPU, making it a self-contained mobile solution.

The Intel Xeon E3-1220 v5 wins in the server and workstation domain, despite losing every benchmark. Its ECC memory support is the standout feature, protecting against data corruption in critical applications. Its support for both DDR3 and DDR4 gives system builders flexibility in memory choice, and the listed 34.1 GB/s memory bandwidth provides a measurable throughput figure. The Intel Socket 1151 platform allows for socketed installation and upgrades, whereas the i7-3840QM is soldered to its board. The Xeon’s 16 PCIe Gen 3 lanes are also listed, providing a clear expansion path for GPUs or NVMe storage. For a headless server, file server, or workstation where a discrete GPU is already required, the Xeon’s reliability features outweigh its 2% performance deficit. The i7-3840QM is the better processor for raw speed, but the Xeon is the better platform for mission-critical, always-on workloads.