AMD has announced new mobile CPUs today expanding the Ryzen 7000 series. It now includes the new Ryzen 5 7545U and Ryzen 3 7440U alongside the previously announced parts. What's special about these two new SKUs is that they are hybrid in nature somewhat similar to Intel's Big-Bigger processors that have been around since Alder Lake (12th Gen). These new 5nm parts are what AMD refers to as "Phoenix 2".
While rumors suggested that this was on the cards with next gen Ryzen 8000 series, it looks like the current gen is already getting the hybrid treatment.
If you notice in the image above, the Ryzen 5 7545U is similarly specced as the previous 7540U though the difference is that some of those cores are Zen 4c on the new 7545U whereas they are all Zen 4 on the 7540U. If you are wondering, on the hexa-core 7545U, four of the cores out of six are Zen 4c while the remaining two are Zen 4. Meanwhile, on the quad-core Ryzen 3 7440U, two of the cores are Zen 4 while the other two are Zen 4c.
AMD says there is a 35% space saving with its Zen 4c cores compared to the full fledged Zen 4. While Zen 4 is designed for higher clocks (performance per core / single-core performance), Zen 4c is optimized for lower clocks (around 3GHz) for better performance per watt.
While at a quick glance, both AMD and Intel are targeting similar things with these hybrid chips, Team Red claims its design is the more versatile one as it will not require special optimization via hardware scheduler for the operating system, like for Windows or Linux.
In a slide (above), AMD explains why exactly this is the case. Essentially, what the company means is that Zen 4c, unlike the Efficiency Cores or E-Cores on Intel, are just like miniature versions of the large Zen 4 cores. Hence, stuff like simultaneous multi-threading (SMT), instructions per cycle (IPC), instruction set, among others, remain same. As mentioned above, only the cache size has been reduced.
This is very much unlike the E-cores on Intel which lack hyper-threading (SMT) and are quite differently designed than the P-cores which is why special optimization via Thread Director was necessary on Windows 11. Linux too has been integrating similar changes to make the Intel hybrid CPUs work better.
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