Amd epyc cache: EPYC «Genoa-X» CPUs With 1.1GB of L3 Cache Now Available

EPYC 7003 Up to 64 Cores and 768 MB L3 Cache

There’s been a lot of focus on how both Intel and AMD are planning for the future in packaging their dies to increase overall performance and mitigate higher manufacturing costs. For AMD, that next step has been V-cache, an additional L3 cache (SRAM) chiplet that’s designed to be 3D die stacked on top of an existing Zen 3 chiplet, tripling the total about of L3 cache available. Today, AMD’s V-cache technology is finally available to the wider market, as AMD is announcing that their EPYC 7003X «Milan-X» server CPUs have now reached general availability.

As first announced late last year, AMD is bringing its 3D V-Cache technology to the enterprise market through Milan-X, an advanced variant of its current-generation 3rd Gen Milan-based EPYC 7003 processors. AMD is launching four new processors ranging from 16-cores to 64-cores, all of them with Zen 3 cores and 768 MB L3 cache via 3D stacked V-Cache.

AMD’s Milan-X processors are an upgraded version of its current 3rd generation Milan-based processors, EPYC 7003. Adding to its preexisting Milan-based EPYC 7003 line-up, which we reviewed back in June last year, the most significant advancement from Milan-X is through its large 768 MB of L3 cache using AMD’s 3D V-Cache stacking technology. The AMD 3D V-Cache uses TSMC’s N7 process node – the same node Milan’s Zen 3 chiplets are built upon – and it measures at 36 mm², with a 64 MiB chip on top of the existing 32 MiB found on the Zen 3 chiplets. 

Focusing on the key specifications and technologies, the latest Milan-X AMD EPYC 7003-X processors have 128 available PCIe 4.0 lanes that can be utilized through full-length PCIe 4.0 slots and controllers selection. This is dependent on how motherboard and server vendors want to use them. There are also four memory controllers that are capable of supporting two DIMMs per controller which allows the use of eight-channel DDR4 memory.

The overall chip configuration for Milan-X is a giant, nine chiplet MCM, with eight CCD dies and a large I/O die, and this goes for all of the Milan-X SKUs. Critically, AMD has opted to equip all of their new V-cache EPYC chips with the maximum 768 MB of L3 cache, which in turn means all 8 CCDs must be present, from the top SKU (EPYC 7773X) to the bottom SKU (EPYC 7373X). Instead, AMD will be varying the number of CPU cores enabled in each CCD. Drilling down, each CCD includes 32 MB of L3 cache, with a further 64 MB of 3D V-Cache layered on top for a total of 96 MB of L3 cache per CCD (8 x 96 = 768).

In terms of memory compatibility, nothing has changed from the previous Milan chips. Each EPYC 7003-X chip supports eight DDR4-3200 memory modules per socket, with capacities of up to 4 TB per chip and 8 TB across a 2P system. It’s worth noting that the new Milan-X EPYC 7003-X chips share the same SP3 socket as the existing line-up and, as such, are compatible with current LGA 4094 motherboards through a firmware update.

AMD EPYC 7003 Milan/Milan-X Processors
AnandTech Core/
PCIe Memory TDP
EYPC 7773X 64 128 2200 3500 768 MB 128 x 4. 0 8 x DDR4-3200 280 $8800
EPYC 7763 64 128 2450 3400 256 MB 128 x 4.0 8 x DDR4-3200 280 $7890
EPYC 7573X 32 64 2800 3600 768 MB 128 x 4.0 8 x DDR4-3200 280 $5590
EPYC 75F3 32 64 2950 4000 256 MB 128 x 4.0 8 x DDR4-3200 280 $4860
EPYC 7473X 24 48 2800 3700 768 MB 128 x 4.0 8 x DDR4-3200 240 $3900
EPYC 74F3 24 48 3200 4000 256 MB 128 x 4. 0 8 x DDR4-3200 240 $2900
EPYC 7373X 16 32 3050 3800 768 MB 128 x 4.0 8 x DDR4-3200 240 $4185
EPYC 73F3 16 32 3500 4000 256 MB 128 x 4.0 8 x DDR4-3200 240 $3521

Looking at the new EPYC 7003 stack with 3D V-Cache technology, the top SKU is the EPYC 7773X. It features 64 Zen3 cores with 128 threads has a base frequency of 2.2 GHz and a maximum boost frequency of 3.5 GHz. The EPYC 7573X has 32-cores and 64 threads, with a higher base frequency of 2.8 GHz and a boost frequency of up to 3.6 GHz. Both the EPYC 7773X and 7573X have a base TDP of 280 W, although AMD specifies that all four EPYC 7003-X chips have a configurable TDP of between 225 and 280 W.

The lowest spec chip in the new line-up is the EPYC 7373X, which has 16 cores with 32 threads, a base frequency of 3. 05 GHz, and a boost frequency of 3.8 GHz. Moving up the stack, it also has a 24c/48t option with a base frequency of 2.8 GHz and a boost frequency of up to 3.7 GHz. Both include a TDP of 240 W, but like the bigger parts, AMD has confirmed that both 16-core and 24-core models will have a configurable TDP of between 225 W and 280 W.

Notable, all of these new Milan-X chips have some kind of clockspeed regression over their regular Milan (max core performance) counterparts. In the case of the 7773X, this is the base clockspeed, while the other SKUs all drop a bit on both base and boost clockspeeds. The drop is necessitated by the V-cache, which at about 26 billion extra transistors for a full Milan-X configuration, eats into the chips’ power budget. So with AMD opting to keep TDPs consistent, clockspeeds have been dialed down a bit to compensate. As always, AMD’s CPUs will run as fast as heat and TDP headroom allows, but the V-cache equipped chips are going to reach those limits a bit sooner.

AMD’s target market for the new Milan-X chips is customers who need to maximize per-core performance; specifically, the subset of workloads that benefit from the extra cache. This is why the Milan-X chips aren’t replacing the EPYC 70F3 chips entirely, as not all workloads are going to respond to the extra cache. So both lineups will be sharing the top spot as AMD’s fastest-per-core EPYC SKUs.

For their part, AMD is particularly pitching the new chips at the CAD/CAM market, for tasks such as finite element analysis and electronic design automation. According to the company, they’ve seen upwards of a 66% increase in RTL verification speeds on Synopsys’ VCS verification software in an apples-to-apples comparison between Milan processors with and without V-cache. As with other chips that incorporate larger caches, the greatest benefits are going to be found in workloads that spill out of contemporary-sized caches, but will neatly fit into the larger cache. Minimizing expensive trips to main memory means that the CPU cores can remain working that much more often.

Microsoft found something similar last year, when they unveiled a public preview of its Azure HBv3 virtual machines back in November. At the time, the company published some performance figures from its in-house testing, mainly on workloads associated with HPC. Comparing Milan-X directly to Milan, Microsoft used data from both EPYC 7003 and EPYC 7003-X inside its HBv3 VM platforms. It’s also worth noting that the testing was done on dual-socket systems, as all of the EPYC 7003-X processors announced today could be used in both 1P and 2P deployments.

Performance data published by Microsoft Azure is encouraging and using its in-house testing, it looks as though the extra L3 cache is playing a big part. In Computational Fluid Dynamics, it was noted that there was a better speed up with fewer elements, so that has to be taken into consideration. Microsoft stated that with its current HBv3 series, its customers can expect maximum gains of up to 80% performance in Computational Fluid Dynamics compared to the previous HBv3 VM systems with Milan.

Wrapping things up, AMD’s EPYC 7003-X processors are now generally available to the public. With prices listed on a 1K unit order basis, AMD says the EPYC 7773X with 64C/128T will be available for around $8800, while the 32C/64T model, the EPYC 7573X, will cost about $5590. Moving down, the EPYC 7473X with 24C/48T will cost $3900, and the entry EPYC 7373X with 16C/32T will cost slightly more with a cost of $4185.

Given the large order sizes required, the overall retail price is likely to be slightly higher for one unit. Though with the majority of AMD’s customers being server and cloud providers, no doubt AMD will have some customers buying in bulk. Many of AMD’s major server OEM partners are also slated to begin offering systems using the new chips, including Dell, Supermicro, Lenovo, and HPE.

Finally, consumers will get their own chance to get their hands on some AMD V-cache enabled CPUs next month, when AMD’s second V-cache product, the Ryzen 7 5800X3D, is released. The desktop processor is based around a single CCD with a whopping 96 MB of L3 cache available, all of which contrasts nicely with the much bigger EPYC chips.

AMD EPYC Genoa-X Wields 1.3 GB of L3 Cache, 96 Cores

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AMD announced a range of new products today at its Data Center and AI Technology Premiere event here in San Francisco, California. The company shared more details about its EPYC Genoa-X processors with up to 1.1GB of L3 cache, which are shipping now. 

AMD also detailed its 5nm EPYC Bergamo processors for cloud-native applications and announced its Instinct MI300 processors that feature 3D-stacked CPU and GPU cores on the same package with HBM, along with a new GPU-only MI300X model that is also used to bring eight accelerators onto one platform that wields an incredible 1.5TB of HBM3 memory. All three of these products are available now, but AMD also has its EPYC Sienna processors for telco and the edge coming in the second half of 2023. 

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(Image credit: AMD)(Image credit: AMD)(Image credit: AMD)(Image credit: AMD)(Image credit: AMD)(Image credit: AMD)

Much like its predecessor, Milan-X, AMD’s new Genoa-X is designed for a range of technical workloads, like CAD design flows and EDA. The chip follows the same design philosophy of the company’s previous-gen EPYC Milan-X processors, which employ 3D V-Cache, a novel new technique that uses hybrid bonding to fuse an additional 64MB of 7nm SRAM cache vertically atop the Ryzen compute chiplet, thus tripling the amount of L3 cache per die. AMD employs its second-gen 3D V-cache with Genoa-X, and you can read the deep-dive details of the hybrid bonding technology here and here.

Swipe to scroll horizontally

Processor Price (1KU) Cores/Threads Base/Boost Clock (GHz) L3 Cache (L3 + 3D V-Cache) TDP cTDP (W)
Genoa-X 9684X $14,756 96 / 192 2. 55 / 3.7 1,152 MB 400W ?
EPYC 7773X $8,800 64 / 128 2.2 / 3.5 768MB 280W 225-280W
Genoa-X 9384X $5,529 32 / 64 3.1 / 3.9 768MB 320W ?
EPYC 7573X $5,950 32 / 64 2.8 / 3.6 768MB 280W 225-280W
EPYC 7473X $3,900 24 / 48 2.8 / 3.7 768MB 240W 225-280W
Genoa-X 9184X $4,928 16 / 32 . 55 / 4.2 768MB 320W ?
EPYC 7373X $4,185 16 / 32 3.05 / 3.8 768MB 240W 225-280W

Genoa-X brings the Zen 4 architecture to bear and kicks the L3 cache up a notch with up to 1.1 GB of L3, a 43% increase over the 768 MB found on the previous-gen model. Genoa-X also tops out at a 96-core model, a marked increase over the previous-gen’s peak of 64 cores. The chips drop directly into existing SP5 sockets, thus leveraging the existing server and workstation ecosystem. The chips top out with a 400W TDP with the 96-core model and extend down to 320W with the 16-core chip. 

AMD provided benchmarks showing Genoa-X going head-to-head with Intel’s 80-core 8490H Xeon with impressive gains, and a comparison with an Intel Xeon with the same number of cores, again exhibiting marked performance gains in various technical workloads.  

Microsft also announced that its Azure cloud have general availability of its new HBv4 and HX-series instances with Genoa-X, and new HBv3 instances. Azure also provided benchmarks to show the performance gains, which top out at 5.7X gains.

We’re running down more details about the chips, stay tuned for updates.  

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AMD Introduces EPYC 9004 (Genoa) Server Processors — Up to 96 Zen 4 Cores, DDR5 and PCIe 5.0 Support

3DNews Technologies and IT market. News Processors AMD Unveils EPYC Milan-X With Technology…

The most interesting in the reviews

08.11.2021 [21:07],

Nikolai Khizhnyak

At the Accelerated Data Center, AMD CEO Lisa Su shared the first official details about EPYC Milan-X server processors using the new 3D V-Cache cache technology, which will increase the L3 cache size of current EPYC processors Milan on Zen 3 architecture up to 768 MB. Thus, systems based on two such processors will receive a total of up to 1.5 GB of L3 cache.

Image Source: Tom’s Hardware

As a quick reminder, AMD first showed off a chip with 3D V-Cache technology at Computex 2021. At that time, the company showed a prototype Ryzen consumer processor equipped with an additional L3 cache stack. The manufacturer explained that 3D V-Cache uses an innovative technology for vertically combining Ryzen processor computing chipsets with an additional die of 64 MB SRAM memory based on a 7nm process technology. Due to this, according to the company, performance in some games increases up to 15%. Ryzen consumer processors with 3D V-Cache technology are expected early next year.

Image source: AMD

AMD decided to use the same technology in its Milan-X server processors. However, the manufacturer, unfortunately, did not provide detailed information about the processors themselves. However, from the company’s early announcements, it is known that Milan-X processors will be represented by 16-, 32- and 64-core models. Previously, the alleged model names and characteristics of EPYC Milan-X processors also appeared on the Web:

Image source: Tom’s Hardware

Each CCD chiplet of current EPYC Milan models contains 32 MB of L3 cache. Due to 3D V-Cache technology, an additional chip of 64 MB of L3 cache memory will be installed on the chiplet. Thus, one eight-core chiplet will have 96 MB of L3 cache. Since the Milan-X processors will be available in models with up to 64 cores in configurations up to 8 CCD chiplets, they will receive a total of up to 768 MB of L3 cache.

Image Source: AMD

An additional layer of L3 cache will increase the total cache latency by about 10%. However, this disadvantage will be mitigated by the increased L3 cache size, since its additional size will reduce the bandwidth load to the main RAM stack, thereby reducing latency and improving performance.

EPYC Milan-X will be based on the same Zen 3 cores. The control scheme for 3D V-Cache was added to the architecture at the design stage. To work, the chips will require the same SP3 processor socket as the regular EPYC Milan. True, a BIOS update is required. But in general, this will greatly simplify the transition to new processors.

Image source: AMD

According to AMD, the use of hybrid L3 cache-to-chiplet technology allows for 200 times higher interconnect density compared to 2D chipsets, as well as 15 times higher density and 3 times higher energy efficiency. compared to 3D packaging using microprotrusions. In addition, the technology improves the heat dissipation and density of transistors compared to other 3D packaging technologies.

The manufacturer also adds that the use of 3D V-Cache will not require any software modifications (except, as mentioned above, a BIOS update). However, AMD is still working with some partners to create certified software products for the new features of the EPYC Milan-X processors.

Image source: AMD

Leveraging 3D V-Cache technology, Milan-X processors will deliver up to 50% faster performance in certain workloads, such as design and simulation software. AMD, for example, noted computational fluid dynamics (CFD), finite element analysis (FEA), structural analysis, and electronic design automation (EDA), including chip design.

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