Intel Core i5-6600

The Intel Core i5-6600 is a desktop processor based on the Skylake architecture, manufactured on Intel's 14 nm process node. It operates with four physical cores and four threads, featuring a base clock of 3.30 GHz and a boost clock of 3.90 GHz. The processor sits in the 39th percentile of all CPUs tracked by this database, with an average benchmark score of 1488, placing it in a tightly contested mid-range segment where performance margins between direct competitors are exceptionally slim.

Benchmark Performance

The Core i5-6600's aggregate benchmark data reveals a processor that is squarely positioned in a dense cluster of comparable silicon. Its average benchmark score of 1488 places it within a narrow band of performance, where the nearest rival, the AMD Opteron 6344, scores 1492, a delta of -0.2 percent. This effectively means the two processors are statistically indistinguishable in overall workload performance, despite their vastly different architectures and market origins.

Looking at the specific Cinebench results, the i5-6600 demonstrates a consistent scaling pattern across generations of the test. In Cinebench R15, it achieves a multicore score of 518 and a single-core score of 72. Moving to Cinebench R20, the multicore score jumps to 2161 while single-core reaches 304. The most recent Cinebench R23 iteration shows a multicore score of 5147 and a single-core score of 726. This progression indicates that the processor's relative standing improves slightly in newer, more demanding workloads, suggesting that its architectural efficiency holds up well as software evolves.

When compared to its immediate rivals, the performance deltas are remarkably small. The i5-6600 trails the Intel Core i7-3770S, which averages 1500 points, by only -0.8 percent. Conversely, it leads the Intel Core i5-7500T by 0.5 percent, as that chip scores 1481, and the Intel Core i5-5575R by 0.8 percent, with that processor scoring 1477. These sub-one-percent differences mean that in real-world usage, the choice between these CPUs would rarely be dictated by raw performance metrics alone, as run-to-run variance in benchmarking often exceeds these margins.

Single-Thread vs Multi-Thread Behavior

The ratio between single-thread and multi-thread performance in the i5-6600 tells a clear story about its design priorities. With four cores and four threads, the processor lacks Hyper-Threading, meaning each core handles exactly one thread. This configuration produces a multicore-to-singlecore ratio in Cinebench R23 of approximately 7.1x, which is a typical figure for a quad-core part without simultaneous multithreading. The single-core Cinebench R23 score of 726 demonstrates strong per-thread efficiency, a hallmark of the Skylake architecture's improved instruction handling and higher IPC compared to older Intel designs.

For real workloads, this split has meaningful implications. Applications that rely heavily on single-thread performance, such as older games, spreadsheet operations, or lightly threaded productivity tools, will see the i5-6600 perform admirably, with its high boost clock of 3.90 GHz ensuring responsive behavior. Conversely, heavily threaded workloads like video encoding, 3D rendering, or modern game engines that scale across many threads will expose the limitation of having only four threads. The multicore Cinebench R23 score of 5147 reflects this ceiling, placing the processor firmly in a tier where it can handle moderate multi-threaded tasks but will lag behind six-core and eight-core competitors that are common in more recent product generations.

The 35-watt TDP is notable in this context, as it suggests the processor is tuned for efficiency rather than raw throughput. This efficiency focus means the i5-6600 can sustain its boost clocks without requiring aggressive cooling, but it also caps the potential for sustained all-core workloads to reach higher frequency levels. The data indicates a processor that excels in bursty, single-threaded scenarios while delivering competent but unremarkable multi-threaded results.

Platform and Compatibility

The i5-6600 utilizes the Intel Socket 1151 interface, which was the mainstream desktop socket for the Skylake generation. The processor supports both DDR3 and DDR4 memory through a dual-channel memory bus, providing a maximum memory bandwidth of 34.1 GB/s. This dual-protocol memory support was a distinctive feature of the early Socket 1151 platform, allowing system builders to reuse existing DDR3 memory or adopt newer DDR4 modules, though the bandwidth ceiling remains the same regardless of memory type chosen.

PCIe connectivity is provided through Gen 3 lanes, with 16 lanes available from the CPU itself. This configuration supports a single high-bandwidth graphics card at full x16 bandwidth or two cards at x8/x8, which was standard for desktop platforms of this era. The integrated graphics solution is the UHD Graphics 530, which provides basic display output capabilities without requiring a discrete graphics card. Notably, ECC memory is not supported, which positions this processor for consumer desktop use rather than workstation or server applications.

The processor was released on 2015-06-30 and has since been marked as end-of-life, meaning it is no longer in active production. The part number is listed as SR2BWSR2L5, and the multiplier is locked, preventing overclocking via the CPU ratio. For users on this platform, the upgrade path is limited to other Socket 1151 processors from the same generation, though the end-of-life status indicates that newer platforms have superseded this socket entirely. The die size is 177 mm², and the cache hierarchy includes 64 KB of L1 per core, 256 KB of L2 per core, and 6 MB of shared L3 cache.

How It Compares

Against the AMD Opteron 6344, the i5-6600 performs essentially identically, with a delta of -0.2 percent. This is a striking result given that the Opteron 6344 is a server-class processor with a fundamentally different architecture and core count, yet the average benchmark scores align within a rounding error. The i5-6600's advantage in single-thread performance and modern instruction set is offset by the Opteron's sheer core count in multi-threaded scenarios, resulting in a statistical tie.

The Intel Core i5-7500T is a closer architectural relative, being a newer Kaby Lake part with a lower TDP. The i5-6600 leads this chip by 0.5 percent, a marginal advantage that suggests the older Skylake design holds its own against its direct successor, albeit with a higher power draw. The performance difference is negligible in practice, and the choice would come down to platform features and power efficiency rather than raw compute capability.

The Intel Core i5-5575R represents an interesting comparison, as it is a Broadwell-based part with the same core and thread count. The i5-6600 edges ahead by 0.8 percent, reflecting the IPC improvements delivered by the Skylake architecture over its predecessor. This small but consistent lead indicates that the architectural refinement in Skylake provided a tangible, if modest, performance uplift.

The Intel Core i7-3770S is the strongest rival in this group, scoring 1500, which puts the i5-6600 behind by -0.8 percent. This is notable because the i7-3770S is an older Ivy Bridge processor that benefits from Hyper-Threading, giving it four cores and eight threads. Despite its age, the extra threads allow it to slightly outpace the i5-6600 in aggregate benchmark scores, demonstrating that thread count can compensate for architectural generational gaps in mixed workloads.

Power and Thermals

The i5-6600 carries a TDP of 35 watts, which classifies it as a low-power desktop processor. This is a significant reduction from the standard 65-watt TDP that was typical for mainstream quad-core Intel parts of its generation, indicating that this model is specifically binned and tuned for energy efficiency. The 35-watt rating means the processor generates considerably less heat than its higher-power counterparts, which directly impacts the required cooling solution.

Given this TDP class, the i5-6600 can be adequately cooled by a stock cooler or a modest low-profile air cooler. The thermal density is low enough that even compact mini-ITX builds with limited airflow would not struggle to keep temperatures in check. The 14 nm process node contributes to this efficiency, as the smaller manufacturing process reduces both power leakage and heat generation compared to older 22 nm or 32 nm parts. The integrated UHD Graphics 530 also benefits from this power budget, as the iGPU shares the same thermal envelope and can operate without causing thermal throttling in typical desktop scenarios.

The locked multiplier reinforces the efficiency focus, as users cannot push the processor beyond its specified boost clock of 3.90 GHz. This means the 35-watt TDP is a reliable indicator of sustained performance, with no headroom for overclocking to increase power draw. For system builders prioritizing low noise and low heat output, the i5-6600 presents a compelling profile, though its end-of-life status means it is only available through secondhand or clearance channels.