KB4091666: Intel microcode updates

Applies to: Windows 10


Intel recently announced that it has completed its validations and has started to release microcode for newer CPU platforms around Spectre Variant 2 (CVE 2017-5715: “Branch Target Injection”). This update includes microcode updates from Intel for the following CPUs.

Product name (CPU) Public name CPUID Intel microcode update revision
Skylake H/S 6th Generation Intel Core Processor Family 506E3 0xC2
Skylake U/Y & Skylake U23e 6th Generation Intel Core m Processors 406E3 0xC2
Skylake Server SP (H0, M0, U0) Intel® Xeon® Bronze Processor 3104, 3106,
Intel® Xeon® Gold Processor 5115, 5118, 5119T, 5120, 5120T, 5122, 6126, 6126F,
6126T, 6128, 6130, 6130F, 6130T, 6132, 6134, 6134M, 6136, 6138, 6138F,
6138T, 6140, 6140M, 6142, 6142F, 6142M, 6144, 6146, 6148,
6148F, 6150, 6152, 6154,
Intel® Xeon® Platinum Processor 8153, 8156, 8158, 8160, 8160F,
8160M, 8160T, 8164, 8168, 8170, 8170M, 8176, 8176F, 8176M, 8180, 8180M,
Intel® Xeon® Silver Processor 4108, 4109T, 4110, 4112, 4114, 4114T, 4116, 4116T 
00050654 0x2000049
Skylake D (Bakerville) Intel® Xeon® Processor D-2123IT, D-2141I, D-2142IT, D2143IT, D-2145NT, D-2146NT, D-2161I,
D-2163IT, D2166NT, D-2173IT, D-2177NT, D-2183IT, D-2187NT
00050654 0x2000049
Skylake X (Basin Falls) Intel® Core™ i9 79xxX, 78xxX 00050654 0x2000049
Broadwell DE A1 Intel® Xeon® Processor D-1513N, D-1523N, D-1533N, D-1543N, D1553N 50665 0xE000009
Broadwell DE V1 Intel® Xeon® Processor D-1520, D-1540 50662 0x15
Broadwell DE V2,V3 Intel® Xeon® Processor D-1518, D-1519, D-1521, D-1527, D-1528, D-1531, D-1533, D-1537, D-1541, D-1548,
Intel® Pentium® Processor D1507, D1508, D1509, D1517, D1519
50663 0x7000012
Broadwell DE Y0 Intel® Xeon® Processor D-1557, D-1559, D-1567, D-1571, D-1577, D-1581, D-1587 50664 0xF000011
Broadwell H 43e Intel® Core™ Processor i7-5950HQ, i7-5850HQ, i7-5750HQ, i7-5700HQ,
Intel® Core™ Processor i5-5575R, i5-5675C, i5-5675R, i7-5775C, i7-5775R,
Intel® Core™ Processor i7-5700EQ, i7-5850EQ 
40671 0x1D
Broadwell U/Y Intel® Core™ Processor i7-5650U,i7-5600U, i7-5557U, i7-5550U, i7-5500U,
Intel® Core™ Processor i5-5350U, i5-5350,i5-5300U, i5-5287U,i5-5257U, i5-5250U, i5-5200U,
Intel® Core™ Processor i3-5157U, i3-5020U, i3-5015U, i3-5010U, i3-5006U, i3-5005U, i3-5010U, i5-5350U, i7-5650U,
Intel® Core™ Processor M-5Y71, M-5Y70, M-5Y51, M-5Y3, M-5Y10c, M -5Y10a, M-5Y10,
Intel® Pentium® Processor 3805U, 3825U, 3765U, 3755U, 3215U, 3205U,
Intel® Celeron® 3765U
306D4 0x2A
Broadwell Xeon E3 Intel® Xeon® Processor v4 E3-1258L, E3-1265L, E3-1278L, E3-1285, E3-1285 40671 0x1D
Broadwell Server E, EP, EP4S

Intel® Xeon® Processor E5-2603V4, E5-2609V4, E5-

2620V4, E5-2623V4, E5-2630LV4, E5-2630V4, E5-

2637V4, E5-2640V4, E5-2643V4, E5-2650LV4, E5-

2650V4, E5-2660V4, E5-2667V4, E5-2679V4, E5-2680V4, E5-2683V4, E5-2690V4, E5-2695V4, E5-2697AV4, E5-2697V4, E5-2698V4, E5-2699AV4, E5-2699V4

Intel® Xeon® Processor E5-2608LV4, E5-2618LV4, E5-

2628LV4, E5-2648LV4, E5-2658V4, E5-2699RV4, E5-

406F1 0xB00002C
Broadwell Server EX

Intel® Xeon® Processor E7-4809V4, E7-4820V4, E7-

4830V4, E7-4850V4, E7-8855V4, E7-8860V4, E7-8867V4, E7-8870V4, E7-8880V4, E7-8890V4, E7-8891V4, E7-8893V4, E7-8894V4
406F1 0xB00002C
Haswell (including H, S), Xeon E3 4th Generation Intel® Core™ Mobile Processor Family,
Intel® Pentium® Mobile Processor Family,
Intel® Celeron® Mobile Processor Family
306C3 0x24
Haswell Perf Halo Intel® Core™ Extreme Processor (5960x, 5930x, 5820x) 40661 0x19
Haswell Server E, EP, EP4S Intel® Xeon® Processor v3 E5-1428L, E5-1603, E5-1607, E5-1620, E5-1630,
E5-1650, E5-1660, E5-1680, E5-2408L, E5-2418L, E5-2428L, E5-2438L, E5-2603, E5-2608L, E5-2608L,
E5-2609, E5-2618L, E5-2620, E5-2623, E5-2628L, E5-2630, E5-2630L, E5-2637, E5-2640, E5-2643,
E5-2648L, E5-2650, E5-2650L, E5-2658, E5-2660, E5-2667, E5-2670, E5-2680, E5-2683, E5-2685,
E5-2687W,E5-2690, E5-2695, E5-2697, E5-2698, E5-2699, E5-4610, E5-4620,
E5-4627, E5-4640, E5-4648, E5-4650, E5-4655, E5-4660, E5-4667, E5-4669
306F2 0x3C
Haswell ULT 4th Generation Intel® Core™ Mobile Processor Family,
Intel® Pentium® Mobile Processor Family,
Intel® Celeron® Mobile Processor Family
40651 0x23
Ivy Bridge 3rd Generation Intel® Core™ Mobile Processor Family,
Intel® Pentium® Mobile Processor Family, and Intel® Celeron® Mobile Processor Family
306A9 0x1F
Ivy Bridge Xeon E3 Intel® Core™ Processor Extreme Edition i7-4960X Intel® Core™ Processor i7-4820K, i7-4930K 306A9 0x1F
Ivy Bridge E, Ivy Bridge Server E, EN, EP, EP4S Intel® Xeon® Processor v2 E5-1428L, E5-1620, E5-1650, E5-1660, E5-2403, E5-2407, E5-2418L,
E5-2420, E52428L, E5-2430, E5-2430L, E5-2440, E5-2448L, E5-2450, E5-2450L, E5-2470, E5-2603, E5-2609, E5-2618L, E52620, E5-2628L, E5-2630,
E5-2630L, E5-2637, E5-2640, E5-2643, E5-2648L, E5-2650, E5-2650L, E5-2658, E52660, E5-2667, E5-2670, E5-2680, E5-2687W, E5-2690, E5-2695, E5-2697, E5-4603, E5-4607, E5-4610, E5-4620,
E5-4624L, E5-4627, E5-4640, E5-4650, E5-4657L 
000306E4 0x42C
Ivy Bridge Server EX E5-4610, E5-4620, E5-4624L, E5-4627, E5-4640, E54650, E5-4657L 000306E7 0x713
Sandy Bridge Intel® Core™ i3-21xx/23xx-T/M/E/UE Processor,
Intel® Core™ i5-23xx/24xx/25xx-T/S/M/K Processor,
Intel® Core™ i7-2xxx-S/K/M/QM/LE/UE/QE Processor,
Intel® Core™ i7-29xxXM Extreme Processor,
Intel® Celeron® Desktop G4xx, G5xx Processor,
Intel® Celeron® Mobile 8xx, B8xx Processor,
Intel® Pentium® Desktop 350, G6xx, G6xxT, G8xx Processor,
Intel® Pentium® Mobile 9xx, B9xx Processor 
206A7 0x2D
Sandy Bridge Xeon E3 Intel® Xeon® Processor E3-1200 Product Family 206A7 0x2D
Sandy Bridge Server EN/EP/EP4S Intel® Xeon® Processor E5-2620, E5-2630, E5-2630L, E52640,
E5-2650, E5-2650L, E5-2660, E5-2667, E5-2670, E5-2680, E5-2690
206D6 0x61C
Sandy Bridge Server EN/EP/EP4S Intel® Xeon® Processor E5-1428L, E5-1620, E5-1650, E51660, E5-2403, E5-2407,
E5-2418L, E5-2420, E5-2428L, E5-2430, E5-2430L, E5-2440, E5-2448L, E5-2450, E52450L,
E5-2470, E5-2603, E5-2609, E5-2620, E5-2630, E5-2630L, E5-2637, E5-2640, E5-2643, E5-2648L,
E52650, E5-2650L, E5-2658, E5-2660, E5-2665, E5-2667, E5-2670, E5-2680, E5-2687W,
E5-2690, E5-4603, E54607, E5-4610, E5-4617, E5-4620, E5-4640, E5-4650,
E5-4650L Intel® Pentium® Processor 1405
206D7 0x713
Knights Landing Intel® Xeon® Phi™ Processor 72xx 50671 0x1B6
Knights Mill Intel® Xeon® Phi™ Processor Family 80650 0x18

Nehalem EP, Nehalem WS

Intel® Xeon® Processor E5502, E5503, E5504, E5506, E5507, E5520, E5530, E5540

Intel® Xeon® Processor L5506, L5508, L5518, L5520, L5530

Intel® Xeon® Processor W5580, W5590

Intel® Xeon® Processor X5550, X5560, X5570




Intel® Core™ Processor i7-860, 860S, 870, 870S, 875K, 880

Intel® Core™ Processor i5-750, 750S, 760



Lynnfield Xeon

Intel® Xeon® Processor L3426

Intel® Xeon® Processor X3430, X3440, X3450, X3460, X3470, X3480




Intel® Core™ Processor i7-i7-620M/LM/UM, i7-640LM/UM

Intel® Core™ Processor i5-430M, i5-520M/UM, i5-540M

Intel® Core™ Processor 330M, 350M

Intel® Celeron® Processor P4500, P4505




Intel® Core™ Processor i5-650, 660, 661, 670

Intel® Core™ Processor i3-530, 540, 550, 560

Intel® Pentium® Processor G6950



Clarkdale Xeon

Intel® Xeon® Processor L3406




Intel® Core™ Processor i7-610E, 620LE/LM/M/UE/UM, 640LM/M/UM, 660LM/UE/UM, 680UM

Intel® Core™ Processor i5-430M/UM, 450M, 460M, 470UM, 480M, 520E/M/UM, 540M/UM, 560M/UM, 580M

Intel® Core™ Processor i3-330E/M/UM, 350M, 370M, 380M/UM, 390M

Intel® Pentium® Processor P6000, P6100, P6200, P6300

Intel® Pentium® Processor U5400, U5600

Intel® Celeron® Processor P4500, P4505, P4600

Intel® Celeron® Processor U3400, U3405, U3600




Intel® Core™ Processor i5-650, 655K, 660, 661, 670, 680

Intel® Core™ Processor i3-530, 540

Intel® Pentium® Processor G6950, G6951, G6960



WestmereEP, WS

Intel® Xeon® Processor E5603, E5606, E5607, E5620, E5630, E5640, E5645, E5649

Intel® Xeon® Processor L5609, L5618, L5630, L5638, L5640

Intel® Xeon® Processor W3670, W3680

Intel® Xeon® Processor X5647, X5650, X5660, X5667, X5670, X5672, X5675, X5677, X5680, X5687, X5690, X5698



This update is a stand-alone update that's available through the Microsoft Update Catalog and targeted to Windows 10 Release To Market (RTM). This update also includes Intel microcode updates that were already released for this operating system at the time of Release To Manufacturing (RTM).

We will offer additional microcode updates from Intel through this article for this operating system as they become available to Microsoft.

Please make sure that mitigation against Spectre Variant 2 is enabled by applying the update through KB 4078407 or through the registry settings that are documented in the following article:

Known issues

Microsoft is not aware of any issues that affect this update currently.

How to obtain and install the update

Method 1: Windows Update

To download and install this update, go to Settings > Update & Security > Windows Update and then select Check for updates. If Windows Update says your device is up to date, you have all the updates that are currently available.

Method 2: Windows Server Update Service

This update is now available for installation through WSUS.

Method 3: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.


Learn about the terminology that Microsoft uses to describe software updates.