If we believe the legends, then Intel produced a Core i5-7660X processor 3 years ago but never officially released it. However, there are times when legends turn out to be reality. A Chinese Twitter user by the username Zed_Wang posted images of a working sample of the processor which belongs to the Skylake-X family on May 27, 2020.
As the images suggest, the processor, without a doubt uses Skylake micro-architecture. Thus, it becomes obvious that the processor is manufactured using Intel’s 14nm+ process node and would slide into the LGA2066 socket, like any other Skylake-X chip. The Core i5-7660X has all of the attributes of Skylake-X, such as support for quad-channel memory (128GB max) and AVX-512 instructions.
It is possible that if Intel would have released the Core i5-7660X at that time, the Hexa-core processor could have been an interesting offer. It would have been Intel’s first Core i5 HEDT(high-end desktop) processor and also the first Core i5 processor to support quad-channel memory.
Specifications and Benchmarks
According to the CPU-Z screenshots posted by Wang, the Intel Core i5-7660X has six cores, six threads, and an 8.25MB L3 cache. These specs suggest that the mythical processor is closely related to the Intel Core i7-7800X processor.
The Core i5-7660X comes with a 3.4GHz of the base clock. Although the base speed of the processor nothing out of the ordinary and extremely impressive, its boost clock speed is another story entirely. The previous Skylane-X family-based processors offered a max boost clock of 4.3GHz whereas the Core i5-7660 processor offers 5 GHz of boost clock. It is also worth mentioning that this boost clock speed was not seen in any of the Core i7 or Core i9 processors released at that time. This boost clock speed of Core i5-7660X processor is the highest amount all of the Skylake-X SKUs.
The processor also provides a 28 PCIe 3.0 lanes and also supports DDR4-2400 memory modules, much similar to Core i7-7800X. At that time only Core i7-7820X and above supported the DDR4-2666 memory modules.
Conclusion
If we have to sum it all up, the Core i5-7660X is similar to a Core i7-7800X. However, it has a higher clock speed but without Hyper-Threading. Although it is rated the same 140W TDP, Intel has used the disabling of Hyper-Threading to a huge advantage. By disabling it, the Core i5-7660X’s boost clock speed can sky-rocket. Intel’s Core i5-7660X could have been a product of their recycling subpar silicon which did not meet the standards for a Core i7-7800X. This would also explain the close similarities between the two HEDT (high-end desktop) processors. Although it was never officially out, the specs and benchmark lead fans to speculate that this mythical processor better than many processors released by Intel that year.
To this day it remains a mystery as to why Intel never officially released the Core i5-7660X. Either the company was too concerned with the lack of interest or it just wanted to keep the HEDT platform for Core i7 and above. Rumors suggest that some of the samples of the Core i5-7660X actually made to the hands of a few select overclockers. After all, this processor is one of a long-gone age, it still was among the best at its time.