Zen 3

Zen 3 is the codename for a CPU microarchitecture by AMD, released on November 5, 2020.[1][3] It is the successor to Zen 2 and uses TSMC's 7 nm process for the chiplets and GlobalFoundries's 14 nm process for the I/O die (as it did with the Ryzen 3000XT processors).[5] Zen 3 powers Ryzen 5000 mainstream desktop processors (codenamed "Vermeer") and Epyc server processors (codenamed "Milan").[6][4] Zen 3 is supported on motherboards with 500 series chipsets; 400 series boards will also see support on select B450 / X470 motherboards with certain beta BIOSes.[7] Zen 3 is expected to be the last microarchitecture before AMD switches to DDR5 memory and new sockets.[3] According to AMD, Zen 3 is 19% faster on average than Zen 2 at the same frequency.

AMD Zen 3

General information
Launched	November 5, 2020[1]
Designed by	AMD
Common manufacturer(s)	TSMC
Cache
L1 cache	64 KiB per core[2]
L2 cache	512 KiB per core[2]
Physical specifications
Cores	6 to 16 (desktop)
Socket(s)	Socket AM4[3] Socket SP3[4]
Products, models, variants
Product code name(s)	Vermeer (desktop) Milan (server)
History
Predecessor	Zen 2

Features

Zen 3 is a significant incremental improvement over its predecessors, with an IPC increase of 19%,[8] and being capable of reaching higher clock speeds.

Like Zen 2, Zen 3 is composed of up to 2 core complex dies (CCD) along with a separate IO die containing the I/O components. A Zen 3 CCD is composed of a single core complex (CCX) containing 8 CPU cores and 32 MB of shared L3 cache, this is in contrast to Zen 2 where each CCD is composed of 2 CCX, each containing 4 cores each as well as 16 MB of L3 cache. The new configuration allows all 8 cores of the CCX to directly communicate with each other and the L3 Cache instead of having to use the IO die through the Infinity Fabric.[8]

Zen 3 also features Smart Access Memory (SAM), a technology allowing Zen 3 processors to directly access all of a compatible graphic card's VRAM,[9] allowing an increased FPS of up to 11% in certain games.[10] SAM is an implementation of resizable BAR, an optional feature introduced in PCIe 2.0 that, as of the launch of Zen 3, only AMD has explored.[11] As of December 2020, Intel and Nvidia are reportedly working on implementing Resizable BAR in the near future.

• 
  A delidded Ryzen 5 5600X. Only one CCD is present. The contacts for a second CCD are visible.
• 
  Close up of the CCD, taken under infrared lighting. The die broke during delidding.
• 
  Close up of the I/O Die

In Zen 3, a single 32MB L3 cache pool is shared among all 8 cores in a chiplet, vs Zen 2's two 16MB pools each shared among 4 cores in a core complex, of which there were two per chiplet. This new arrangement improves the cache hit rate as well as performance in situations that require cache data to be exchanged among cores, but increases cache latency from 39 cycles in Zen 2 to 46 clock cycles and halves per-core cache bandwidth, although both problems are partially mitigated by higher clock speeds. Total cache bandwidth on all 8 cores combined remains the same due to power consumption concerns. L2 cache capacity and latency remain the same at 512KB and 12 cycles. All cache read and write operations are done at 32 bytes per cycle.[2]

Improvements

Zen 3 has made the following improvements over Zen 2:[2][12]

• An increase of 19% in instructions per clock
• The base core chiplet has a single eight-core complex (versus two four-core complex in Zen 2)
• A unified 32MB L3 cache pool equally available to all 8 cores in a chiplet, vs Zen 2's two 16MB pools each shared among 4 cores in a core complex.
• Increased branch prediction bandwidth. L1 branch target buffer size increased to 1024 entries (vs 512 in Zen 2)
• Improved integer units
  • 96 entry integer scheduler (up from 92)
  • 192 entry physical register file (up from 180)
  • 10 issue per cycle (up from 7)
  • 256 entry reorder-buffer (up from 224)
  • fewer cycles for DIV/IDIV ops (10...20 from 16...46)
• Improved floating point units
  • 6 µOP dispatch width (up from 4)
  • 4 cycles for fused-multiply-add-ops (down from 5)

Feature tables

CPUs

CPU features table

APUs

APU features table

Products

On October 8, 2020, AMD announced four Zen 3-based desktop Ryzen processors, consisting of one Ryzen 5, one Ryzen 7, and two Ryzen 9 CPUs and featuring between 6 and 16 cores.[1]

Vermeer

Model	Release date and price	Fab	Chiplets	Cores (threads)	Core config[lower-roman 1]	Clock rate (GHz)		Cache			Socket	PCIe lanes	Memory support	TDP
						Base	Boost	L1	L2	L3
Mainstream
Ryzen 5 5600X[13]	November 5, 2020 US $299	TSMC 7FF	1 × CCD 1 × I/O	6 (12)	1 × 6	3.7	4.6	32 KiB data 32 KiB inst. per core	512 KiB per core	32 MiB	AM4	24	DDR4-3200 dual-channel	65 W
Performance
Ryzen 7 5800[14]	January 12, 2021 OEM	TSMC 7FF	1 × CCD 1 × I/O	8 (16)	1 × 8	3.4	4.6	32 KiB data 32 KiB inst. per core	512 KiB per core	32 MiB	AM4	24	DDR4-3200 dual-channel	65 W
Ryzen 7 5800X[15]	November 5, 2020 US $449					3.8	4.7							105 W
Enthusiast
Ryzen 9 5900[16]	January 12, 2021 OEM	TSMC 7FF	2 × CCD 1 × I/O	12 (24)	2 × 6	3.0	4.7	32 KiB data 32 KiB inst. per core	512 KiB per core	32 MiB per CCD	AM4	24	DDR4-3200 dual-channel	65 W
Ryzen 9 5900X[17]	November 5, 2020 US $549					3.7	4.8							105 W
Ryzen 9 5950X[18]	November 5, 2020 US $799			16 (32)	2 × 8	3.4	4.9

1. Active Core Complexes (CCX) × Active cores per CCX.

Cezanne

Model	Release date	Fab	CPU							GPU			Socket	PCIe lanes	Memory support	TDP
			Cores (threads)	Core config[lower-roman 1]	Clock rate (GHz)		Cache			Model, config[lower-roman 2]	Clock	Processing power (GFLOPS)[lower-roman 3]
					Base	Boost	L1	L2	L3
Ryzen 3 5400U[19]	January 12, 2021	TSMC 7FF	4 (8)	1 x 4	2.6	4.0	32 KiB inst. 32 KiB data per core	512 KiB per core	8 MiB	AMD Radeon Graphics 6 CU	1600 MHz	-	FP6	16 (8+4+4)	DDR4-3200 LPDDR4-4266 dual-channel	10–25 W
Ryzen 5 5600U[20]			6 (12)	2 × 3	2.3	4.2			16 MiB	AMD Radeon Graphics 7 CU	1800 MHz
Ryzen 5 5600H[21]					3.3											35–54 W
Ryzen 5 5600HS[22]					3.0
Ryzen 7 5800U[23]			8 (16)	2 × 4	1.9	4.4				AMD Radeon Graphics 8 CU	2000 MHz					10–25 W
Ryzen 7 5800H[24]					3.2											35–54 W
Ryzen 7 5800HS[25]					2.8
Ryzen 9 5900HS[26]					3.0	4.6					2100 MHz
Ryzen 9 5900HX[27]					3.3
Ryzen 9 5980HS[28]					3.0	4.8
Ryzen 9 5980HX[29]					3.3

1. Active Core Complexes (CCX) × active cores per CCX.
2. Unified shaders : texture mapping units : render output units and compute units (CU)
3. Single precision performance is calculated from the base (or boost) core clock speed based on a FMA operation.

Epyc microprocessors

The Epyc server line of chips based on Zen 3 is to be named Milan and will be the final generation of chips using the SP3 socket.[4]

References

1. Su, Lisa (October 8, 2020). Where Gaming Begins, AMD Ryzen™ Desktop Processors.
2. Cutress, Ian; Frumusanu, Andrei (November 5, 2020). "AMD Zen 3 Ryzen Deep Dive Review: 5950X, 5900X, 5800X and 5600X Tested". www.anandtech.com. Retrieved December 7, 2020.
3. Joel Hruska (January 10, 2020). "AMD's Lisa Su Confirms Zen 3 Coming in 2020, Talks Challenges in Notebooks". ExtremeTech.
4. Alcorn, Paul (October 5, 2019). "AMD dishes on Zen 3 and Zen 4 architecture, Milan and Genoa roadmap". Tom's Hardware. Retrieved October 5, 2019.
5. Dr. Ian Cutress (October 9, 2020). "AMD Ryzen 5000 and Zen 3 on Nov 5th: +19% IPC, Claims Best Gaming CPU". AnandTech.
6. Mark Knapp (October 8, 2020). "AMD Zen 3 release date, specs and price: everything we know about AMD Ryzen 5000". TechRadar.
7. Hruska, Joel (May 20, 2020). "AMD Will Support Zen 3, Ryzen 4000 CPUs on X470, B450 Motherboards". ExtremeTech. Retrieved May 20, 2020.
8. "AMD "Zen 3" Core Architecture". AMD. Retrieved November 8, 2020.
9. Alcorn, Paul (November 6, 2020). "AMD Zen 3 Ryzen 5000 Price, Specs, Release Date, Performance, All We Know". Tom's Hardware. Retrieved November 8, 2020.
10. "AMD Smart Access Memory". AMD. Retrieved November 8, 2020.
11. https://www.pcgamer.com/amd-smart-access-memory-not-proprietary-promise
12. Alcorn, Paul (November 26, 2020). "AMD Ryzen 9 5950X and 5900X Review: Zen 3 Breaks the 5 GHz Barrier". www.tomshardware.com. Retrieved December 25, 2020.
13. "AMD Ryzen™ 5 5600X Desktop Processor". AMD.
14. "AMD Ryzen™ 7 5800". AMD.
15. "AMD Ryzen™ 7 5800X Desktop Processor". AMD.
16. "AMD Ryzen™ 9 5900". AMD.
17. "AMD Ryzen™ 9 5900X Desktop Processor". AMD.
18. "AMD Ryzen™ 9 5950X Desktop Processor". AMD.
19. "AMD Ryzen™ 3 5400U". AMD.
20. "AMD Ryzen™ 5 5600U". AMD.
21. "AMD Ryzen™ 5 5600H". AMD.
22. "AMD Ryzen™ 5 5600HS". AMD.
23. "AMD Ryzen™ 7 5800U". AMD.
24. "AMD Ryzen™ 7 5800H". AMD.
25. "AMD Ryzen™ 7 5800HS". AMD.
26. "AMD Ryzen™ 9 5900HS". AMD.
27. "AMD Ryzen™ 9 5900HX". AMD.
28. "AMD Ryzen™ 9 5980HS". AMD.
29. "AMD Ryzen™ 9 5980HX". AMD.