Intel Core i-11000 for desktop PCs: fewer CPU cores, but new architecture


Intel’s 11th generation of the Core i processors Rocket Lake competes with a total of 19 CPUs from the Core i5, i7 and i9 series with six and eight cores respectively. For the first time since 2015, the chip manufacturer has revised the arithmetic units of its desktop processors. Compared to the predecessor Core i-10000, the computing power per clock should increase by up to 19 percent thanks to the Cypress Cove cores and that of the Xe graphics unit by up to 50 percent.

CPUs with two and four cores from the Pentium Gold and Core i3 series will not be available with the new technology. Instead, Intel is offering updated models of the tenth generation of Core i that use the same LGA1200 version.

Actually, all Intel processors should have been rolling off the assembly line in the 10 nanometer process for years, but the ambitious goal of increasing the packing density by a factor of 2.7 led to numerous delays. In order not to let the gap to the Ryzen competition grow even further, Intel has therefore tackled Rocket Lake as Plan B: Over the past two years, the Sunny Cove design of the 10 nm Core i-1000G ( Ice Lake) backported to 14 nm and combined with the more modern Xe graphics unit of the successor Core i-1100G (Tiger Lake).

The new CPU architecture of the Core i-11000 should pay off especially for 3D games.

(Image: Intel)

The higher performance is due to the larger level 1 and level 2 caches as well as to wider arithmetic units: Internally there are now 10 instead of 8 execution units (ports) and an additional address generation and store unit. In addition, there are shortened load latencies and an improved jump prediction.

With Rocket Lake, the vector instruction set extension AVX512 also finds its way into Intel’s mainstream desktop processors. Until now, this was reserved for server and mobile chips in various sub-dials. AVX512 is only granted a short guest appearance: In the next generation Alder Lake it will be omitted, only the newly added crypto and AI functions Vector Neural Network Instructions (VNNI), which Intel also calls DL Boost (Deep Learning).

The Cypress Cove architecture is identical to Sunny Cove from the Core i-1000 “Ice Lake” mobile CPUs.

(Image: Intel)

The top model Core i9-11900K has a similarly high clock frequency of up to 5.3 GHz compared to the ten-core predecessor Core i9-10900K, but two cores less. Because by backporting the 10-nanometer design to a 14-nanometer production, the space requirement of the die increases significantly. Intel did not want to disclose specific figures. A decapitated copy of the previously sold Core i7-11700K is around 260 mm² larger than the previous ten-core die of the Core i9-10900K (around 200 mm²).

In order to minimize costs, Intel only produces one die type (8 CPU cores, 32 GPU units) and partially switches them off for the six cores. This, and the fact that Intel is already planning the successor Alder Lake with hybrid architecture for autumn 2021, predicts a comparatively short lifespan for Rocket Lake.

With Rocket Lake, Intel is sticking to the tried and tested ring bus, which links the various function blocks in the processor with one another.

(Image: Intel)

The memory controller can now handle DDR4-3200 instead of DDR4-2933. However, the memory controller only runs in the so-called Gear-1 mode with the same clock rate on the Core i9-11900K. All other CPUs only achieve DDR4-3200 in the so-called Gear-2 mode at half the clock frequency of the controller, which increases the latencies. The maximum speed for Gear 1 is DDR4-2933. This is probably one of the compromises that Intel had to make when adopting the Ice Lake mobile design.

Compared to the UHD 630 (Gen 9.5), Intel has completely redesigned the UHD 750 graphics unit (Gen 12) of the Core i-11000. It now has 32 instead of 24 units, which are also significantly more powerful with the Xe architecture. It also brings the long overdue HDMI 2.0, for which mainboard manufacturers previously had to solder DisplayPort converters. The GPU relieves the CPU cores, for example, when playing AV1 videos with 10-bit color depth (hardware decoding).