ARM Cortex-X4

ARM Cortex-X4

General information
Launched	2023
Designed by	ARM Ltd.
Performance
Address width	40-bit
Cache
L1 cache	128 KiB (64 KiB I-cache with parity, 64 KiB D-cache) per core
L2 cache	512–2048 KiBper core
L3 cache	512 KiB – 32 MiB(optional)
Architecture and classification
Microarchitecture	ARM Cortex-X4
Instruction set	ARMv9.2-A
Physical specifications
Cores	1–10 (per cluster)
Products, models, variants
Product code name	"Hunter ELP"
Variant	ARM Cortex-A720
History
Predecessor	ARM Cortex-X3
Successor	ARM Cortex-X925

The ARM Cortex-X4 is a high-performance CPU core from Arm, released in 2023 ^[1] as part of Arm's "total compute solution". ^[2] It serves as the successor of ARM Cortex-X3. ^[3]

X-series CPU cores generally focus on high performance, and can be grouped with other ARM cores, such as ARM Cortex-A720 or/and ARM Cortex-A520 in a System-on-Chip (SoC). ^{[4] [5]}

Architecture changes in comparison with ARM Cortex-X3

The processor implements the following changes: ^{[3] [4] [5]}

• ARMv9.2
• micro-op (MOP) cache removed (previously 1.5k entries)
• Decode width: 10
• Rename / Dispatch width: 10 (increased from 8)
• Reorder buffer (ROB): 384 entries (increased from 320)
• Execution ports: 21 (increased from 15)
• Pipeline length: 10 (increased from 9)
• Up to 2 MiB of private L2 cache (increased from 1 MiB)
• DSU-120
  • Up to 14 cores (up from 12 cores)
  • Up to 32 MiB of shared L3 cache (increased from 16 MiB)

Performance claims:

• 15% peak performance improvement over the Cortex-X3 in smartphones

(3.4GHz, 2MB L2, 8MB L3). ^[5]

• 13% IPC uplift over the Cortex-X3, when based on the same process, clock speed,

and L3 cache (but 2 MiB L2 vs 1 MiB L2) setup (also known as ISO-process). ^[5]

Architecture comparison

"Prime" core

uArch	Cortex-A78	Cortex-X1	Cortex-X2	Cortex-X3	Cortex-X4	Cortex-X925
Code name	Hercules	Hera	Matterhorn-ELP	Makalu-ELP	Hunter-ELP	Blackhawk
Architecture	ARMv8.2		ARMv9		ARMv9.2
Peak clock speed	~3.0 GHz			~3.3 GHz	~3.4 GHz	~3.8 GHz
Decode width	4	5		6	10 [6]
Dispatch	6/cycle	8/cycle			10/cycle
Max in-flight	2x 160	2x 224	2x 288	2x 320	2x 384	2x 768
L0 (Mops entries)	1536 [7]	3072 [7]		1536	0 [6]
L1-I + L1-D	32+32 KiB	64+64 KiB
L2	128–512 KiB	0.25–1 MiB			0.5–2 MiB	2–3 MiB
L3	0–8 MiB [8]		0–16 MiB		0–32 MiB

Usage

• Google • Tensor G4 ^[9]
• MediaTek • Dimensity 9300/9300+ ^[10]
• Qualcomm • Snapdragon 8 Gen 3 (2023) ^[11]

See also

• ARM Cortex-A520, related high efficient microarchitecture
• ARM Cortex-A720, related efficient sustained performance microarchitecture
• Comparison of ARMv8-A cores

References

1. "Arm Total Compute Solution 2023 targets premium smartphones". embedded.com. 2023-06-02. Retrieved 2024-01-17.
2. "TCS23: The complete platform for consumer computing - Arm Community". community.arm.com. 2023-05-29. Retrieved 2023-09-16.
3. "Arm introduces the Cortex-X4, its newest flagship performance core". WikiChip Fuse. 2023-05-28. Retrieved 2023-05-30.
4. "Arm Cortex-X4 advances frontiers of CPU performance - Arm Community". community.arm.com. 2023-05-29. Retrieved 2023-09-16.
5. "Arm Unveils 2023 Mobile CPU Core Designs: Cortex-X4, A720, and A520 - the Armv9.2 Family". www.anandtech.com. Retrieved 2023-05-30.
6. "Arm Cortex-X4, A720, and A520: 2024 smartphone CPUs deep dive". Android Authority. 2023-05-29. Retrieved 2023-06-01.
7. "Arm's New Cortex-A78 and Cortex-X1 Microarchitectures: An Efficiency and Performance Divergence". anandtech.com. Retrieved 2023-06-01.
8. Schor, David (2020-05-26). "Arm Cortex-X1: The First From The Cortex-X Custom Program". WikiChip Fuse. Retrieved 2023-05-30.
9. "Latest Pixel 9 leak gives us a look at the Tensor G4 specs and benchmarks". Android Authority. 2024-06-01. Retrieved 2024-06-01.
10. "MediaTek says its Snapdragon 8 Gen 3 rival will be a beast (Updated)". Android Authority. 2023-05-29. Retrieved 2023-09-16.
11. "Qualcomm Snapdragon Tech Summit Live Blog: Compute Spotlight". Android Authority. 2023-05-29. Retrieved 2023-09-16.