AMD Epyc 7643 VS AMD Ryzen 9 3900 — differences in specs

Comparing AMD Epyc 7643 vs AMD Ryzen 9 3900

Comparison of video cards AMD Epyc 7643 vs AMD Ryzen 9 3900 in benchmarks and specifications.

Differences Specifications Benchmarks

Differences

Top features of AMD Epyc 7643

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More number of cores

48 12

2 times more threads

Top features of AMD Ryzen 9 3900

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Higher clock speed

3.10 GHz 2.30 GHz

Around 26% better clock speed
Higher turbo clock speed

4.30 GHz 3.60 GHz

Around 16 % better overclocked clock speed
Performance per watt

65 W 280 W

About 0.23 times less performance per watt

Specifications

Complete list of technical specifications

AMD Epyc 7643 AMD Ryzen 9 3900

CPU generation and family

Let's find out which one of AMD Epyc 7643 and AMD Ryzen 9 3900 is of a more recent generation, and what segment it belongs to.

Specification	Value
Name	AMD Epyc 7643 AMD Ryzen 9 3900
Segment	Desktop / Server Desktop / Server
Family	AMD Epyc AMD Ryzen
Generation	3 3
CPU group	AMD Epyc 7003 AMD Ryzen 3000
Predecessor	AMD Epyc 7642 --
Successor	-- AMD Ryzen 9 5900

CPU Cores and Base Frequency

In this block we are going to compare AMD Epyc 7643 vs AMD Ryzen 9 3900 by main technical specifications: number of cores and threads, base and maximum frequencies, process technology and cache size. The higher these specifications are, the more powerful your CPU will be.

Specification	Value
Frequency	2.30 GHz 3.10 GHz
CPU Cores	48 12
Turbo (1 Core)	3.60 GHz 4.30 GHz
CPU Threads	96 24
Hyperthreading	Yes Yes
Overclocking	No Yes
Core architecture	normal normal

Internal Graphics

Common specifications for integrated graphics cards in AMD Epyc 7643 and AMD Ryzen 9 3900 along with supported interfaces and connection options. This block has no effect on the final efficiency of the CPU.

Specification	Value
GPU name	no iGPU no iGPU
GPU (Turbo)	No turbo No turbo

Hardware codec support

Let's compare the support of video codecs between AMD Epyc 7643 and AMD Ryzen 9 3900. Hardware support of video decoding by embedded graphics cards directly affects the speed and quality of rendering videos.

Specification	Value
h265 / HEVC (8 bit)	No No
h265 / HEVC (10 bit)	No No
h264	No No
VP9	No No
VP8	No No
AV1	No No
AVC	No No
VC-1	No No
JPEG	No No

Memory & PCIe

To choose the best model between AMD Epyc 7643 and AMD Ryzen 9 3900 you need to pay special attention to memory type, clock frequency, multi-channel features, and PCIe version. The higher these numbers are, the better your CPU will be. Keep in mind that the maximum memory and frequency may also depend on the model of the motherboard.

Specification	Value
Memory type	DDR4-3200 DDR4-3200
Max. Memory	128 GB
ECC	Yes No
Memory channels	8 2
PCIe version	4.0 4.0
PCIe lanes	128 20

Encryption

AES-NI encryption support for CPUs AMD Epyc 7643 and AMD Ryzen 9 3900.

Specification	Value
AES-NI	Yes Yes

Thermal Management

Let's find out what TDP value would be better for AMD Epyc 7643 or AMD Ryzen 9 3900? The Thermal Design Power (TDP) indicates the maximum amount of heat that should be dissipated by the chip cooling system. However, the value of TDP gives only a rough indication of the real power consumption of the CPU.

Specification	Value
TDP (PL1)	280 W 65 W
Tjunction max.	-- 95 °C

Technical details

Here you can find a comparison of 2nd and 3rd level cache sizes for AMD Epyc 7643 and AMD Ryzen 9 3900 CPUs along with a list of ISA extensions.

Specification	Value
Instruction set (ISA)	x86-64 (64 bit) x86-64 (64 bit)
Virtualization	AMD-V, SVM AMD-V, SVM
ISA extensions	SSE4a, SSE4.1, SSE4.2, AVX2, FMA3 SSE4a, SSE4.1, SSE4.2, AVX2, FMA3
L3-Cache	256.00 MB 64.00 MB
Architecture	Milan (Zen 3) Matisse (Zen 2)
Technology	7 nm 7 nm
Socket	SP3 AM4
Release date	Q1/2021 Q3/2019