IntelBX80662I56600K
IntelBX80684I58400

4 Cores, 4 Threads
@3.5GHz Skylake (2015)

6 Cores, 6 Threads
@2.8GHz Coffee Lake (2017)

Real World Speed
Performance profile from 121,153 user samples
111,329 User Benchmarks
Best Bench: 107% Base clock 3.5 GHz, turbo 4.8 GHz (avg)
Worst Bench: 70% Base clock 3.5 GHz, turbo 0.75 GHz (avg)
Poor: 70% Great: 107%
SPEED RANK: 38th / 1100
Gaming
Gaming 89%
Aircraft carrier
Desktop
Desktop 86%
Aircraft carrier
Workstation
Workstation 54%
Yacht
9,824 User Benchmarks
Best Bench: 96% Base clock 2.8 GHz, turbo 3.85 GHz (avg)
Worst Bench: 85% Base clock 2.8 GHz, turbo 3.8 GHz (avg)
Poor: 85% Great: 96%
SPEED RANK: 30th / 1100
Gaming
Gaming 92%
Nuclear submarine
Desktop
Desktop 89%
Aircraft carrier
Workstation
Workstation 67%
Battle cruiser
Effective Speed
Effective CPU Speed
89.1 % 92 % +3%
SC Mixed
Avg. Single Core Mixed Speed
122 Pts +2% 120 Pts
QC Mixed
Avg. Quad Core Mixed Speed
463 Pts 467 Pts +1%
MC Mixed
Avg. Multi Core Mixed Speed
473 Pts 684 Pts Much faster multi-core speed.
+45%
SC Mixed
OC Single Core Mixed Speed
145 Pts Faster OC single-core speed.
+16%
125 Pts
QC Mixed
OC Quad Core Mixed Speed
564 Pts Faster OC quad-core speed.
+16%
486 Pts
MC Mixed
OC Multi Core Mixed Speed
567 Pts 722 Pts Faster OC multi-core speed.
+27%
Market Share
Based on 8,450,868 CPUs tested.
Market Share
Market Share (trailing 30 days)
1.13 % +3% 1.1 %
Value
Value For Money
98.7 % 110 % Slightly better value.
+12%
User Rating
UBM User Rating
87 % 107 % More popular.
+23%
Price
Price (score)
$222 $179 Cheaper.
+19%
Age
Newest
32 Months 6 Months Hugely more recent.
+81%
TDP
Thermal Design Power (TDP)
91 Watts 65 Watts More energy efficient.
+29%
Cores
CPU Processing Cores
4 cores 6 cores Much higher core count.
+50%
Threads
CPU Processing Threads
4 threads 6 threads Much higher thread count.
+50%
Lithography
Manufacturing process
14 nm 14 nm
Base Clock
Base Clock Speed
3.5 GHz Faster base frequency.
+25%
2.8 GHz
Turbo Clock
Turbo Clock Speed
3.9 GHz 4 GHz +3%
SC Int
Single Core Integer Speed
141 Pts Faster single-core int speed.
+16%
122 Pts
SC Float
Single Core Floating Point Speed
149 Pts Faster single-core fp speed.
+16%
129 Pts
QC Int
Quad Core Integer Speed
549 Pts Faster quad-core int speed.
+16%
474 Pts
QC Float
Quad Core Floating Point Speed
584 Pts Faster quad-core fp speed.
+16%
503 Pts
MC Int
Multi Core Integer Speed
550 Pts 703 Pts Faster multi-core int speed.
+28%
MC Float
Multi Core Floating Point Speed
585 Pts 744 Pts Faster multi-core fp speed.
+27%
Series
CPU Architecture
Skylake (2015) Coffee Lake (2017)
Socket
Motherboard Socket
FCLGA1151 FCLGA1151
Graphics
Integrated Graphics
HD 530 UHD 630
Launch Date
Launch Date
Q3'15 Q4'17
Cache
Cache
6 MB SmartCache 9 MB
Instruction Set Extensions
Instruction Set Extensions
SSE4.1/4.2, AVX 2.0 SSE4.1/4.2, AVX2
Recommended Price
Recommended Customer Price
$242.00 - $243.00 N/A
Thermal Solution Specification
Thermal Solution Specification
PCG 2015D (130W) PCG 2015C (65W)
Memory Types
Memory Types
DDR4-1866/2133, DDR3L-1333/1600 @ 1.35V DDR4-2666
Processor Graphics
Processor Graphics ‡
Intel® HD Graphics 530 Intel® UHD Graphics 630
Graphics Max Dynamic Frequency
Graphics Max Dynamic Frequency
1.15 GHz 1.05 GHz
TSX-NI
Intel® TSX-NI
Yes No
PCI Express Configurations
PCI Express Configurations ‡
Up to 1x16, 2x8, 1x8+2x4 Up to 1x16 or 2x8 or 1x8+2x4

More specs » More specs »
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The Intel Core i5-6600K is based on the new "Skylake" 14nm manufacturing process. Sporting 4 physical cores with base/turbo clocks of 3.5/3.9 GHz the 6600K and its predecessor, the 4690K share the same basic configuration and disappointingly, offer similar performance. Comparing the 6600K and 6700K shows that the 6700K has faster multi and single core performance. The improved multi core performance is due to Hyperthreading which is the key differentiator for the i7-6700K. The gap in single core performance can largely be eliminated by overclocking the i5-6600K so although the stock effective speed is significantly higher on the 6700K, this gap diminishes significantly when both processors are overclocked. At a 30% discount, the 6600K is the better value gaming CPU. [Aug '15 CPUPro]

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The i5-8400 is a competitively priced hex-core processor from Intel’s 8th generation of Core processors (Coffee Lake). Along with the release of the unlocked i5-8600K, this is the first time that six-core processors have featured in the i5 line-up. Like the other Coffee Lake processors, the i5-8400 is based upon an improved version of Intel’s 14nm architecture which featured in both Skylake and Kaby Lake. Early benchmarks reveal that for average quad core usage (most games employ a maximum of four cores) the i5-8400 performs way above its pay grade. It achieves quad core mixed speeds close to Intel’s outgoing 2017 flagship the $300, quad-core, 8 thread i7-7700k, which to date has been a strong favourite for high-end gaming setups. On paper, the i5-8400 has a base clock of 2.8 GHz (Intel are significantly downplaying the performance of this SKU by giving it a relatively low nominal base clock), an all core boost of 3.8 GHz (this is the effective base clock figure that counts) and a single core boost of 4 GHz. This compares reasonably well to the i5-8600K which has a base clock of 3.6 GHz, all core boost of 4.1 GHz and a single core boost of 4.3 GHz. The i5-8400 also features 9MB of L3 cache and an energy-thrifty TDP of 65W. Priced at under $190, the i5-8400 offers fantastic value for money. Unfortunately, like the other Coffee Lake processors, the i5-8400 will require a new 300 series motherboard, and at the time of writing, the only available version is Intel’s high-end Z370 which isn't an ideal pairing for the i5-8400. The Z series motherboards are designed to cater for the unlocked and overclockable "K" SKUs. Cheaper 300 series motherboards will be available in 2018 at which time the 8400 will offer even better value for money. [Oct '17 CPUPro]

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Processor Rankings (Price vs Performance) April 2018 CPU Rankings.

We calculate effective speed which measures real world performance for typical consumers. Effective speed is adjusted by current prices to yield a value for money rating which is geared towards gamers. Our calculated values are checked against thousands of individual user ratings. The customizable table below combines these factors to bring you the definitive list of top CPUs. [CPUPro]

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Group Test Results

  • Best user rated - User sentiment trumps benchmarks for this comparison.
  • Fastest real world speed - Real World Speed measures performance for typical consumers.
  • Best value for money - Value for money is based on real world performance and price.
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Intel Core i7-8700K $330Nvidia GTX 1070 $447Samsung 850 Evo 250GB $90
Intel Core i7-7700K $290Nvidia GTX 1060-6GB $300Samsung 850 Evo 500GB $137
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HDDRAMUSB
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