AMD’s New EPYC 7F52 Reviewed: The F is for ᴴᴵᴳᴴ Frequency

[harlan4096]

Everyone wants a fast processor. The ability to get more stuff done is one of a number of guiding principles of business. However, business also needs consistency, safety and security, which is why having enterprise-class processors is often a requirement in the back-end infrastructure. These processors, with lots of cores, aren’t as fast as consumer processors, so it becomes a tussle whether it makes sense to go fast without security, or to play it safe with a proven platform. With AMD’s new 7F processors, the aim is to provide that proven platform with super-fast cores with lots of cache. We’ve got the 7F52 in for testing today.

The Enterprise Market Wants It All

The nature of enterprise processors in recent generations has tended towards more cores and more cache. As power budgets have increased, in order to ensure stability and get the best efficiency points, the solution has been to add more cores. However, there are still markets that want high frequency components, and quite often users will look at consumer hardware, which doesn’t offer the trimmings of the enterprise world, such as ECC memory, RAS features, management, and high-speed IO. We’ve seen OEMs build servers on super rare ‘consumer-grade’ processors, like the auction-only 5 GHz 14-core parts that offer the peak of performance, but fall down on basic enterprise features, such as ECC memory.

To that end, AMD’s Enterprise division has been developing some high-frequency processors within its EPYC line of hardware to address this market. We saw with the first generation ‘Naples’ EPYC processors AMD come out with a special EPYC 7371 processor, which offered 16 cores but had +700 MHz on the base frequency and +900 MHz on the turbo frequency compared to the next best 16-core part, and the tradeoff was only +30 W of power and paying a bit extra. At the time the EPYC 7371, which was launched several months after the rest of the product line, was a test run for what is this new line of 7F ‘high frequency’ processors.

AMD 7F and 7H: Targeting High Performance

The best way to consider AMD’s EPYC processor line, especially for the second generation ‘Rome’ hardware, is in four segments.

First is the main stack. These are the regular processors for the majority of the market, from the 7252 with eight cores all the way up to the 7742 with 64 cores. These are all dual-socket compatible, and are anywhere from 155 W to 225 W (except the 7252 and 7262 which are 120 W).

Second are the single socket processors. These are variants of the main stack but designated with a P at the end, as these are built for systems that only require a single processor. The benefit here is that the P processors are actually cheaper ($2600 for the 32-core 7502 compared to $2300 for the 7502P) if the customer can guarantee they never need a dual socket design. These also go from 8 cores all the way up to 64 cores.

Third is the 7H family of processors, which as it stands only has one member right now. This was launched a couple of months after the first two segments, and the ‘H’ stands for High Performance Computing. The power limits of this chip has increased up to 280 W, and the goal is to drive a higher sustained frequency than the regular parts. For example, the 7742 has a base frequency of 2.25 GHz at 225W, but the 7H12 has a base frequency of 2.60 GHz at 280 W. The 7H processors aren’t on general retail as far as we can tell, but specific customers can request them.

Fourth is the newest set of hardware, the 7F family. The F in this case is for Frequency, and these parts are spiritual successors to the 7371 in the last generation: a lot more base frequency and a lot higher turbo for the consumer to use. AMD is also equipping these processors with lots of cache, so the cache per core can effectively quadruple.

For the 8 core 7F32 and the 16 core 7F52, AMD is enabling 1 core per CCX, or 2 cores per chiplet, which means the equivalent of 16 MB of L3 cache per core. This is four times as much as what any other AMD EPYC processor gets.

The 24 core 7F72 is cheaper than the 16 core, as AMD is adjusting the level of cache on offer here to 192 MB. This means that this processor only has six of the eight chiplets active, and each CCX will have two cores active (6 chiplets * 2 CCX per chiplet * 2 cores per CCX = 24). The frequency is a little bit lower because of the increased active core density, so along with the decreased cache, AMD felt the need to price this one below that of the 7F52.
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