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Ryzen Threadripper PRO 3955WX
General Info
Designer	AMD
Manufacturer	TSMC, GlobalFoundries
Model Number	PRO 3955WX
Part Number	100-000000167, 100-100000167WOF
Market	Workstation
Introduction	July 14, 2020 (launched)
Shop	Amazon
General Specs
Family	Ryzen Threadripper
Series	3900
Locked	Yes
Frequency	3,900 MHz
Turbo Frequency	4,300 MHz
Clock multiplier	39
CPUID	0x00830F10
Microarchitecture
ISA	x86-64 (x86)
Microarchitecture	Zen 2
Chipset	WRX80
Core Name	Castle Peak
Core Family	23
Core Model	49
Core Stepping	B0
Process	7 nm, 12 nm
Transistors	15,940,000,000
Technology	CMOS
MCP	Yes (3 dies)
Word Size	64 bit
Cores	16
Threads	32
Max Memory	2 TiB
Multiprocessing
Max SMP	1-Way (Uniprocessor)
Electrical
TDP	280 W
TDP (Typical)	233 W
Tjunction	0 °C – 90 °C
Packaging
Package	sWRX8, FCLGA-4094 (FC-OLGA)
Dimension	75.4 mm × 58.5 mm × 6.26 mm
Pitch	0.87 mm × 1 mm
Contacts	4094
Socket	sWRX8

Ryzen Threadripper PRO 3955WX is a 64-bit 16-core high performance x86 workstation microprocessor introduced by AMD in mid-2020. This multi-chip processor, which is based on their Zen 2 microarchitecture, incorporates two Core Complex Dies fabricated on a TSMC 7 nm process and an I/O die fabricated on a GlobalFoundries 12 nm process. The PRO 3955WX has a TDP of 280 W with a base frequency of 3.9 GHz and a boost frequency of up to 4.3 GHz. This processor supports up to 2 TiB of octa-channel DDR4-3200 memory.

Cache

Main article: Zen 2 § Cache

[Edit/Modify Cache Info]

Cache Organization Cache is a hardware component containing a relatively small and extremely fast memory designed to speed up the performance of a CPU by preparing ahead of time the data it needs to read from a relatively slower medium such as main memory. The organization and amount of cache can have a large impact on the performance, power consumption, die size, and consequently cost of the IC. Cache is specified by its size, number of sets, associativity, block size, sub-block size, and fetch and write-back policies. Note: All units are in kibibytes and mebibytes.

L1$ 1 MiB 1,024 KiB 1,048,576 B L1I$ 512 KiB 524,288 B 0.5 MiB 16 × 32 KiB 8-way set associative   L1D$ 512 KiB 524,288 B 0.5 MiB 16 × 32 KiB 8-way set associative write-back L2$ 8 MiB 8,192 KiB 8,388,608 B 0.00781 GiB     16 × 512 KiB 8-way set associative write-back L3$ 64 MiB 65,536 KiB 67,108,864 B 0.0625 GiB     4 × 16 MiB 16-way set associative write-back

Memory controller

This processor supports UDIMM, RDIMM, LRDIMM, and 3DS RDIMM memory. The maximum memory capacity is 2 TiB using eight 256 GiB LRDIMMs or 3DS RDIMMs.

[Edit/Modify Memory Info]

	Integrated Memory Controller
	Max Type DDR4-3200 Supports ECC Yes Max Mem 2 TiB Controllers 8 Channels 8 Max Bandwidth 204.8 GB/s 190.735 GiB/s 195,312.5 MiB/s 204,800 MB/s 0.186 TiB/s 0.205 TB/s Bandwidth Single 25.6 GB/s Double 51.2 GB/s Quad 102.4 GB/s Octa 204.8 GB/s

Expansions

Main article: Castle Peak § I/O Interfaces

[Edit/Modify Expansions Info]

	Expansion Options
PCIe Revision: 4.0 Max Lanes: 128 Configuration: x16, x8, x4, x2, x1 SATA Revision: 3.2 Max Ports: 32 USB Revision: 3.2 Gen 2×1 Max Ports: 4 Rate: 10 Gbit/s

Graphics

This processor has no integrated graphics.

Features

[Edit/Modify Supported Features]

Supported x86 Extensions & Processor Features

MMX MMX Extension EMMX Extended MMX Extension SSE Streaming SIMD Extensions SSE2 Streaming SIMD Extensions 2 SSE3 Streaming SIMD Extensions 3 SSSE3 Supplemental SSE3 SSE4.1 Streaming SIMD Extensions 4.1 SSE4.2 Streaming SIMD Extensions 4.2 SSE4a Streaming SIMD Extensions 4a AVX Advanced Vector Extensions AVX2 Advanced Vector Extensions 2 ABM Advanced Bit Manipulation BMI1 Bit Manipulation Instruction Set 1 BMI2 Bit Manipulation Instruction Set 2 FMA3 3-Operand Fused-Multiply-Add AES AES Encryption Instructions RdRand Hardware RNG SHA SHA Extensions ADX Multi-Precision Add-Carry CLMUL Carry-less Multiplication Extension F16C 16-bit Floating Point Conversion x86-16 16-bit x86 x86-32 32-bit x86 x86-64 64-bit x86 Real Real Mode Protected Protected Mode SMM System Management Mode FPU Integrated x87 FPU NX No-eXecute SMT Simultaneous Multithreading AMD-Vi AMD-Vi (I/O MMU virtualization) AMD-V AMD Virtualization TSME Transparent SME SenseMI SenseMI Technology

Bibliography

• "AMD Announce World’s First 64-Core PRO Workstation, the Lenovo™ ThinkStation™ P620, the Pinnacle of Performance for Modern Professionals" (Press release). AMD.com. July 14, 2020.
• "AMD Ryzen™ Threadripper™ PRO 3955WX" AMD.com.
• "AMD Family 17h Models 30h-3Fh sWRX8 Processors Power and Thermal Data Sheet", AMD Publ. #56447, Rev. 1.01, August 2020
• "Revision Guide for AMD Family 17h Models 30h-3Fh Processors", AMD Publ. #56323, Rev. 0.78, February 2021