Intel Xeon (server)
Clearwater Forest
Intel Clearwater Forest (2026) supports x86-64-v3.
- x86-64 level
- x86-64-v3
- Vendor
- Intel
- First products
- 2026
- Products
- Xeon 6+ with E-cores
- Segments
- Cores
- Darkmont E-cores only
- GCC target
-march=clearwaterforest- Optimization
- Optimizing code for Darkmont
Product lines
Why not x86-64-v4?
Clearwater Forest lacks AVX512BW, AVX512CD, AVX512DQ, AVX512F and AVX512VL, all of which x86-64-v4 requires.
Feature checklist
| Feature | Clearwater Forest | Enumerated by | Linux flag |
|---|---|---|---|
| x86-64-v1 | |||
| CMOV | Yes | CPUID.01H:EDX[15] | cmov |
| CX8 | Yes | CPUID.01H:EDX[8] | cx8 |
| FPU | Yes | CPUID.01H:EDX[0] | fpu |
| FXSR | Yes | CPUID.01H:EDX[24] | fxsr |
| MMX | Yes | CPUID.01H:EDX[23] | mmx |
| OSFXSR via FXSR | Yes | CPUID.01H:EDX[24] | fxsr |
| SCE | Yes | CPUID.80000001H:EDX[11] | syscall |
| SSE | Yes | CPUID.01H:EDX[25] | sse |
| SSE2 | Yes | CPUID.01H:EDX[26] | sse2 |
| x86-64-v2 | |||
| CMPXCHG16B | Yes | CPUID.01H:ECX[13] | cx16 |
| LAHF-SAHF | Yes | CPUID.80000001H:ECX[0] | lahf_lm |
| POPCNT | Yes | CPUID.01H:ECX[23] | popcnt |
| SSE3 | Yes | CPUID.01H:ECX[0] | pni |
| SSE4.1 | Yes | CPUID.01H:ECX[19] | sse4_1 |
| SSE4.2 | Yes | CPUID.01H:ECX[20] | sse4_2 |
| SSSE3 | Yes | CPUID.01H:ECX[9] | ssse3 |
| x86-64-v3 | |||
| AVX | Yes | CPUID.01H:ECX[28] | avx |
| AVX2 | Yes | CPUID.(EAX=07H,ECX=0):EBX[5] | avx2 |
| BMI1 | Yes | CPUID.(EAX=07H,ECX=0):EBX[3] | bmi1 |
| BMI2 | Yes | CPUID.(EAX=07H,ECX=0):EBX[8] | bmi2 |
| F16C | Yes | CPUID.01H:ECX[29] | f16c |
| FMA | Yes | CPUID.01H:ECX[12] | fma |
| LZCNT | Yes | CPUID.80000001H:ECX[5] | abm |
| MOVBE | Yes | CPUID.01H:ECX[22] | movbe |
| OSXSAVE via XSAVE | Yes | CPUID.01H:ECX[26] | xsave |
| x86-64-v4 | |||
| AVX512F | No | CPUID.(EAX=07H,ECX=0):EBX[16] | avx512f |
| AVX512BW | No | CPUID.(EAX=07H,ECX=0):EBX[30] | avx512bw |
| AVX512CD | No | CPUID.(EAX=07H,ECX=0):EBX[28] | avx512cd |
| AVX512DQ | No | CPUID.(EAX=07H,ECX=0):EBX[17] | avx512dq |
| AVX512VL | No | CPUID.(EAX=07H,ECX=0):EBX[31] | avx512vl |
Other extensions
Notable extensions outside the x86-64 levels. Vendors sometimes disable these on individual models. Linked names lead to the extension's instructions.
- AES-NI
- PCLMULQDQ
- SHA
- RDRAND
- RDSEED
- ADX
- CLWB
- WAITPKG
- MOVDIRI
- MOVDIR64B
- CLDEMOTE
- GFNI
- VAES
- VPCLMULQDQ
- AVX-VNNI
- AVX-IFMA
- AVX-VNNI-INT8
- AVX-NE-CONVERT
- PREFETCHI
Known vulnerabilities
The CVEs that the sources of the vulnerability list name as affecting Clearwater Forest, in all of its models or in some of them.
- CVE-2024-36242 Intel processor errata: Sub-page permission
- CVE-2022-28693 Retbleed: Restricted RSB Alternate behavior
- CVE-2022-26373 Spectre variant 2: Post-barrier Return Stack Buffer Predictions
- CVE-2022-0002 Spectre variant 2: Intra-mode Branch Target Injection
- CVE-2022-0001 Spectre variant 2: Branch History Injection
- CVE-2021-0089 Speculative Code Store Bypass
- CVE-2021-0086 Floating Point Value Injection
- CVE-2019-1125 Spectre variant 1: Spectre v1 swapgs
- CVE-2018-3639 Speculative Store Bypass
- CVE-2017-5753 Spectre variant 1: Bounds Check Bypass
- CVE-2017-5715 Spectre variant 2: Branch Target Injection
Other Intel Xeon (server) microarchitectures
- Skylake-SP 2017 v4
- Cascade Lake 2019 v4
- Cooper Lake 2020 v4
- Ice Lake (server) 2021 v4
- Emerald Rapids 2023 v4
- Sapphire Rapids 2023 v4
- Granite Rapids 2024 v4
- Sierra Forest 2024 v3
- Clearwater Forest 2026 v3
- Diamond Rapids announced v4
Sources
- GCC -march=clearwaterforest feature set (PTA_CLEARWATERFOREST)
- Intel Architecture Instruction Set Extensions and Future Features Programming Reference, 319433-062, Table 1-2: Lists Granite Rapids, Clearwater Forest and Nova Lake as the first processors with PREFETCHIT0 and PREFETCHIT1.
- Linux 7.3 arch/x86/include/asm/intel-family.h: INTEL_ATOM_DARKMONT_X, Clearwater Forest
- Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 4, 335592-093, Table 2-1: Model 06_DDH: Xeon 6+ E-core processors, Clearwater Forest.
- Intel ARK: Products formerly Clearwater Forest: Launch dates; the earliest is Q2'26 (Xeon 6990E+).