Short answer: Yes, with limits. Broadcom KB 428874 was updated on 18 September 2026. Intel Skylake-SP (Xeon Scalable 1st generation: Platinum 8100, Gold 6100/5100, Silver 4100, Bronze 3100) is now supported in Deprecated mode for all of VCF 9.x, including 9.0 GA. Support depends on BCG listing and OEM hardware support. It will not be extended beyond 9.x. Skylake-W (Xeon W-2100) remains discontinued.
This post covers Skylake specifically. For the general installer warning (“may not be supported in future ESXi releases”) and the full CPU tables, see KB 82794 explained.
Intel Skylake ESXi 9 support at a glance
| Skylake variant | BCG CPU series | CPU Info / CPUID | KB 318697 status for 9.x |
|---|---|---|---|
| Skylake-SP | Xeon Platinum 8100, Gold 6100/5100, Silver 4100, Bronze 3100 | 6.55.4 / 0x00050654 | See KB 428874: Deprecated mode for VCF 9.x |
| Skylake-D | Xeon D-2100 | 6.55.4 / 0x00050654 | See KB 428874 |
| Skylake-S | Xeon E3-1200-v5, E3-1500-v5 | 6.5E.3 / 0x000506E3 | See KB 428874 |
| Skylake-W | Xeon W-2100 | 6.55.4 / 0x00050654 | Discontinued |
Note: the text of KB 428874 names only Skylake-SP explicitly. KB 318697 points the Skylake-D and Skylake-S rows to it as well. If you run Xeon D-2100 or E3 v5 systems, check the BCG listing for your exact server model. The other VCF 9 hardware checks (I/O devices, deprecated drivers, vSAN ESA) are in How to check VCF 9 hardware compatibility.
How Skylake support changed from vSphere 8 to VCF 9.x
- vSphere 8.x: Skylake was on the deprecation list. The ESXi 8 installer warned that the CPU may not be supported in future releases, and installation continued. The original version of this post (October 2024) covered that stage.
- VCF 9.0 GA: Skylake-SP was discontinued and not listed in the BCG for 9.0. In February 2026, Broadcom’s VCF blog still said Skylake needed an RPQ, with “VCF Software Only” support on approval.
- KB 428874, 4 July 2026: the KB added Skylake-SP support for VCF 9.1.x.
- KB 428874, 18 September 2026: support was expanded to VCF 9.x, including 9.0 GA. No TQ/RPQ is required for certain OEM server models marked “VCF Supported. Confirm w/ Vendor”.
Advice from older posts and forums, such as “Skylake does not install on ESX 9” or “file an RPQ”, may be out of date. Check the KB’s update date before you decide.
What Deprecated mode means for an Intel Skylake server
- Deprecated means still supported. Per KB 318697, the CPU series is supported through the life of the VCF release, its updates and patches, or until End of General Support.
- The OEM must list the server model in the Broadcom Compatibility Guide. KB 428874 links a BCG search for Skylake systems marked “VCF Supported. Confirm w/Vendor” on ESXi 9.0 and 9.1.
- “VCF Supported. Confirm w/Vendor” means no further system-level driver enhancements and best-effort fixes or workarounds for the VCF software only.
- Hardware, BIOS, firmware and microcode support comes from the server OEM and Intel under your contract with them. If you have no such support, you carry the risk.
- vSAN OSA and ESA ReadyNodes with Skylake-SP are also in Deprecated mode and still supported.
Installing or upgrading ESX 9 on Skylake-SP
KB 428874 says the specific install and upgrade paths for VCF 9.x are described in its attached document, ESX_9.x_Install_Upgrade_using_OVERRIDE_on_Skylake_CPU_based_Servers-v1.3-09182026.pdf. Download it from the KB page and follow it for your path (fresh install, ESX upgrade, or a VCF-managed upgrade). I have not reproduced its steps here because they are versioned and still changing. This is Broadcom’s supported procedure. Don’t confuse it with the unsupported homelab boot option allowLegacyCPU=true.
Is it Skylake or Cascade Lake? Check the stepping
Skylake-SP and Cascade Lake-SP use the same family and model (hex 6.55, decimal model 85). Only the stepping tells them apart: 4 is Skylake-SP, and 6 or 7 is Cascade Lake. Cascade Lake is Deprecated in 9.x and listed as Discontinued for the next major release.
esxcli hardware cpu list
# look at: Brand, Family, Model, Stepping (decimal values)
# Family 6, Model 85, Stepping 4 -> Skylake-SP (6.55.4)
# Family 6, Model 85, Stepping 6/7 -> Cascade Lake (6.55.6 / 6.55.7)What happens after 9.x
KB 428874 is explicit: Skylake-SP support will not be extended to VCF releases beyond 9.x. In KB 318697’s definitions, a “future major release” is the release after the 9.x series. The same table lists Cascade Lake, AMD EPYC 7001 (Naples) and 7002 (Rome), Coffee Lake Xeon E-2100/E-2200 and Atom C3000 as discontinued in that release. For planning:
- Inventory hosts by CPU stepping, not only by server model.
- Treat Skylake-SP hosts as “last stop: VCF 9.x” and track the 9.x End of General Support date in the Broadcom Product Lifecycle Matrix.
- Confirm OEM hardware and firmware support for the remaining lifetime. KB 428874 puts this responsibility on the OEM and Intel.
- Plan the refresh so the cluster does not block the next major upgrade. Avoid mixing in new Cascade Lake purchases, which hit the same wall.
Sources
- Broadcom KB 428874: Deprecated CPU Systems / Servers in ESX 9.0 and implications for support (updated 18 September 2026)
- Broadcom KB 318697: CPU Support Deprecation and Discontinuation In VCF Releases (legacy KB 82794)
- VCF blog: VCF 9.0 Server Certification (February 2026)
