AMD Ryzen Threadripper 3990X vs Intel Core i7-6700K Comparison

Head-to-Head Benchmarks

The recorded data presents an emphatic, one-sided comparison. Across the eight shared benchmark tests, the AMD Ryzen Threadripper 3990X wins all eight, with no victories for the Intel Core i7-6700K. The margins, however, tell a more nuanced story than the raw win count.

The most dramatic deltas appear in the Cinebench suite. In Cinebench R15 multicore, the Threadripper 3990X scores 6866 against the i7-6700K's 765, a delta of 797.5%. The single-core R15 test shows a similar, almost identical gap: 969 versus 108, a delta of 797.2%. This pattern repeats in Cinebench R20 and R23. For R20 multicore, the scores are 28612 against 3189 (797.2% delta), and for R20 single-core, 4039 against 450 (797.6% delta). In Cinebench R23, the multicore result is 68124 versus 7594, and the single-core result is 9617 versus 1072, both showing a 797.1% delta.

These deltas are remarkably consistent, hovering near the 797% mark across all Cinebench iterations. This consistency suggests the performance ratio is tied directly to the structural differences between the two processors, rather than varying with specific workload characteristics within the Cinebench engine.

The Geekbench results offer a different perspective. The multicore test shows a substantial but smaller gap: the Threadripper 3990X scores 20912, while the i7-6700K scores 5011, a delta of 317.3%. More striking is the single-core Geekbench result, where the Threadripper 3990X scores 1472 and the i7-6700K scores 1442, a delta of just 2.1%. This is the only head-to-head test where the two processors are remotely comparable.

The data indicates that while the Threadripper 3990X dominates in all shared tests, its advantage is overwhelmingly concentrated in multi-threaded workloads. The single-core advantage is real but narrow, at least in the Geekbench measurement. The Cinebench single-core tests, by contrast, show a massive 797% delta, which is an outlier compared to the Geekbench single-core data. This discrepancy between benchmark suites highlights how different test methodologies can produce divergent pictures of single-thread performance.

Where Each One Wins

Based strictly on the recorded benchmarks, the AMD Ryzen Threadripper 3990X wins in every category where both processors were tested. There is no benchmark in the head-to-head set where the Intel Core i7-6700K takes the lead.

The Threadripper 3990X's decisive advantage lies in multi-threaded, heavily parallel workloads. The Cinebench R23 multicore score of 68124 versus 7594, a 797.1% delta, exemplifies this. The Geekbench multicore result, with a 317.3% delta, reinforces the same conclusion: applications that scale across many cores will see a massive performance uplift on the Threadripper 3990X. This is the clear use case for this processor.

For single-threaded tasks, the picture is more complex. The Geekbench single-core test shows a 2.1% delta in favor of the Threadripper 3990X, indicating near parity. However, the Cinebench single-core tests show a 797% delta in favor of the Threadripper 3990X, which is inconsistent with the Geekbench data. If we take the Geekbench result as representative, then for lightly-threaded, single-core-bound applications, the two processors are effectively equivalent, with the Threadripper 3990X holding only a marginal edge.

The Intel Core i7-6700K does not post a single winning benchmark in this comparison. Its only potential area of relevance, based on the data, is in the single-core Geekbench test where it comes within 2.1% of the Threadripper 3990X. For users whose workloads are purely single-threaded and who prioritize that specific metric, the i7-6700K is not at a significant disadvantage. However, the database shows no test where it actually wins.

Architecture Differences

The architectural gap between these two processors is vast, explaining the benchmark results. The AMD Ryzen Threadripper 3990X is built on the Zen 2 architecture, codenamed Castle Peak, and belongs to the 3000 series. It uses a 7 nm process node from TSMC, with a die size of 8x 74 mm² and 30,400 million transistors. The Intel Core i7-6700K uses the Skylake architecture, also codenamed Skylake, and is built on Intel's 14 nm process with a die size of 122 mm².

The core and thread counts are the most obvious differentiators. The Threadripper 3990X features 64 cores and 128 threads. The i7-6700K features 4 cores and 8 threads. This 16x difference in core count and 16x difference in thread count directly drives the massive multicore benchmark deltas.

Clock speeds present a contrasting picture. The i7-6700K has a base clock of 4.00 GHz and a boost clock of 4.20 GHz. The Threadripper 3990X has a lower base clock of 2.90 GHz but a higher boost clock of 4.30 GHz. The higher boost clock on the Threadripper 3990X helps explain its single-core Geekbench advantage, while the lower base clock is a trade-off for managing the thermal and power envelope of 64 cores.

Cache hierarchies are fundamentally different in design. The Threadripper 3990X has 64 KB of L1 cache per core and 512 KB of L2 cache per core, with a massive 256 MB of L3 cache. The i7-6700K also has 64 KB of L1 cache per core, but only 256 KB of L2 cache per core, and a shared 8 MB of L3 cache. The Threadripper 3990X's L3 cache is 32 times larger, which is critical for feeding 64 cores with data.

Memory support and I/O also diverge sharply. The Threadripper 3990X supports DDR4 memory over a quad-channel bus, with a theoretical memory bandwidth of 102.4 GB/s. It also provides PCIe Gen 4 with 64 lanes from the CPU. The i7-6700K supports DDR3 and DDR4 memory (depending on the motherboard) over a dual-channel bus, with a memory bandwidth of 34.1 GB/s. Its PCIe is Gen 3 with 16 lanes. The Threadripper 3990X offers roughly triple the memory bandwidth and four times the PCIe lanes, with a newer PCIe generation. The i7-6700K includes integrated graphics (HD Graphics 530), while the Threadripper 3990X has none. Neither processor supports ECC memory. The Threadripper 3990X has a 280 W TDP and uses the AMD Socket TRX4, while the i7-6700K has a 91 W TDP and uses the Intel Socket 1151. Both have unlocked multipliers.

FAQ

Q: Which processor is faster in multi-threaded workloads?

A: The AMD Ryzen Threadripper 3990X is significantly faster. In Cinebench R23 multicore, it scores 68124 versus the Intel Core i7-6700K's 7594, a delta of 797.1%. In Geekbench multicore, it scores 20912 versus 5011, a delta of 317.3%.

Q: How do the two compare in single-threaded performance?

A: The data is mixed. In Geekbench single-core, the Threadripper 3990X scores 1472 and the i7-6700K scores 1442, a 2.1% delta. However, in Cinebench R23 single-core, the Threadripper 3990X scores 9617 against 1072, a 797.1% delta, showing a massive advantage.

Q: What are the core and thread counts for each?

A: The AMD Ryzen Threadripper 3990X has 64 cores and 128 threads. The Intel Core i7-6700K has 4 cores and 8 threads.

Q: What is the difference in memory bandwidth?

A: The Threadripper 3990X supports quad-channel DDR4 with a bandwidth of 102.4 GB/s. The i7-6700K supports dual-channel DDR3 or DDR4 with a bandwidth of 34.1 GB/s.

Q: Do these processors have integrated graphics?

A: The Intel Core i7-6700K includes HD Graphics 530. The AMD Ryzen Threadripper 3990X has no integrated graphics.

Q: What is the process node for each processor?

A: The Threadripper 3990X is built on TSMC's 7 nm process. The i7-6700K is built on Intel's 14 nm process.

The Verdict

The data is unambiguous. The AMD Ryzen Threadripper 3990X is the superior processor in every benchmark where both were measured. Its multicore performance is in a completely different class, with deltas of 797.1% in Cinebench R23 and 317.3% in Geekbench multicore. This makes it the clear choice for any workload that can utilize its 64 cores and 128 threads, such as rendering, scientific computing, or content creation.

The Intel Core i7-6700K, with its 4 cores and 8 threads, cannot compete in these heavily parallel scenarios. Its only point of relevance is the single-core Geekbench test, where it comes within 2.1% of the Threadripper 3990X. For a user whose software is strictly single-threaded and who measures performance by that specific metric, the i7-6700K is not significantly behind. However, the database records no test where the i7-6700K wins.

The choice should be driven by the workload. For multi-threaded, parallel tasks, the AMD Ryzen Threadripper 3990X is the definitive selection, offering a roughly 797% improvement in Cinebench multicore scores. For single-threaded tasks, the Geekbench data suggests the two are nearly equivalent, with a 2.1% delta, making the Threadripper 3990X still the nominal winner. Given that the Threadripper 3990X wins all eight head-to-head tests, the overall recommendation from the recorded data is clear: the AMD Ryzen Threadripper 3990X is the better processor across the board.