ASUS ROG Rampage VI Extreme Encore review - Core X series processors

Core i9 and Core X series processors

Intel has been expanding with an up-to 18-core and thus 36-threads processor actually for two years now. Intel markets these series ass the Core X series, and also has been adding the denominator, the Core i9 series. The processors are paired with the chipset X299 and socket LGA2066. The review sample submitted is the Core i9-10980XE Extreme, the top-of-the-range processor with 18 cores and 36 processing threads. Its Base / Turbo frequency is 3.00 / 4.60 GHz (TB2)  / 4.80 (TB3) GHz with 24.75 MB of L3 cache, 72 PCI-Express 3.0 lines, DDR4 @ 2933 MHz Quad-Channel memory configuration and with a 165W TDP. I refer to TB2 and TB3 as:

• Intel Turbo Boost Technology 2.0: Dynamically increases the processor frequency up to 4.6 GHz when applications demand more performance. Speed when you need it, energy efficiency when you don’t.
• Intel Turbo Boost Max Technology 3.0: Identifies the four best-performing cores to provide increased single- and dual-core performance up to 4.8 GHz, quad-core performance up to 4.7 GHz. 

Cascade Lake-X processors offer an increase in clock frequencies and thus performance, as well as addressing security fixes in hardware, better protection against side-channel attacks. Also, note that this generation allows you to use more memory in volume size, making a move from 128GB towards 256GB supported. Cascade Lake-X offers slightly more PCIe Gen 3.0 lanes - 48 PCIe 3.0 lanes (up from 44). In intel's documentation you' ll notice them mentioning Wi-Fi 6 and 2.5GbE support for these new processors, don't get confused as that is not native, the controllers simply are compatible, and motherboard manufacturers can opt to add-in the appropriate modules. 

Intel Cascade Lake-X	Cores Threads	Base	All Core	TB2	TB3	TDP	Price
Core i9-10980XE	18C / 36T	3.0	3.8	4.6	4.8	165 W	$979
Core i9-10940X	14C / 28T	3.3	4.1	4.6	4.8	165 W	$784
Core i9-10920X	12C / 24T	3.5	4.3	4.6	4.8	165 W	$689
Core i9-10900X	10C / 20T	3.7	4.3	4.5	4.7	165 W	$590
Skylake-X
Core i9-9980XE	18C / 36T	3.0		4.5	4.7	165 W	$1979
Core i9-9940X	14C / 28C	3.3		4.5		165 W	$1387
Core i9-9920X	12C / 24T	3.5		4.5		165 W	$1189
Core i9-9900X	10C / 20T	3.5		4.5		165 W	$989

Architecture changes

The Core i9 series processors have genuinely been based up-on the Skylake architecture that you know from the socket 1151 parts, but then scaled upwards and from there on you have seen tweaks and fabrication process updates. So that means Intel is still at its 14nm node. It’s always hard to tell how correct that number is, as Intel in the past simply increase clock frequencies and called that an IPC increase. That, opposed to expensive architecture changes in caches and so on.  However Intel over the past generations did change caches, the L2 cache, for example, has been increased from 256 kB towards 1 MB per core, which really is significant.  However, relative to that the L3 cache is 1.375 MB per core. With these processors, you will also see two Turbo modes dubbed 2.0 and 3.0 as explained in the first paragraph of this page.

Processor Socket and PCIe

Cascade Lake -X processor series will keep its Socket 2066 on the new X299 chipset platform. All you need is a firmware update to get the new processors compatible from the microcode. 

• Skylake-X 9000 procs gets 44 PCI-Express Lanes 3.0
• Cascade Lake-X 10000 gets 48 PCI-Express Lanes 3.0

So 48 PCIe 3.0 Lanes for the most high-end Cascade Lake-X models, not including the 6 and 8-core parts which will get 28 PCIe lanes. Of course, in-between the processor and the chipset there is an interlink, DMI (revision 3.0)  using four PCIe 3.0 lanes.

	Broadwell-E	Kaby Lake-X	Skylake-X	Cascadelake-X
CPU cores	6, 8, 10	4	6, 8, 10, 12, 14, 16, 18	10, 12, 14 18
Cache	Up to 25MB	8MB	24.75MB	24.75MB
PCIe support	PCIe 3.0 (40/28 lanes)	PCIe 3.0 (16 lanes)	PCIe 3.0 (44/28 lanes)	PCIe 3.0 (48/28 lanes)
Integrated graphics	No	No	No	No
TDP	140W	112W	140W	165E
Socket	LGA 2011-v3	LGA 2066	LGA 2066	LGA 2066
Chipset	X99	X299	X299	X299
Memory support	Quad-channel DDR4	Dual DDR4	Quad-channel DDR4	Quad-channel DDR4