Intel Core i9-9900X socket: LGA 2066

What the Core i9-9900X is

The Core i9-9900X is a ten core, twenty thread HEDT processor with a 3.5 GHz base, up to 4.4 GHz turbo and up to 4.5 GHz on favored cores. It carries 19.25 MB of shared L3 cache and a 165 W TDP on the 14 nm process. Intel announced it on October 8, 2018 with the 9th Gen Core X refresh.

It adds 200 MHz base and nearly 3 MB of cache over the 9820X in the same 165 W band, which suits buyers who want the faster ten core bin. Ten cores cover rendering and compilation with higher clocks for mixed play. The multiplier is unlocked for tuning on X299 boards.

There is no integrated graphics, so a separate card is required. The launch price was $989.00 Intel RCP. Boards need an X299 BIOS with 9th Gen X support from late 2018.

Socket and motherboard compatibility

The 9900X fits LGA 2066 on X299 motherboards with quad channel DDR4. Boards sold before the 9th Gen launch need a BIOS update with the new IDs before the chip will start. The Socket vs chipset: what decides whether a CPU works guide explains chipset support by generation.

X299 carries the chip with up to 68 platform PCIe lanes across CPU and chipset links. A board with heatsinked voltage stages suits long renders at 165 W. Check the maker CPU list for the minimum BIOS per board.

The chip ships without any cooler and mounts on the large LGA 2066 pattern. The Intel Core i9-10900X is the later 10 core successor on the same boards with faster memory support.

Memory, PCIe and cooling

Memory support is DDR4-2666 in four channels up to 128 GB, with up to 85 GB per sec of bandwidth. ECC is not supported. Four matched sticks give quad channel speed, with room for a second set where the board has eight slots.

PCI Express arrives as version 3.0 with 44 lanes from the CPU for graphics and NVMe arrays. Two graphics cards and two fast SSDs fit the lane budget of a creator tower. Cooling needs a large tower or liquid loop at 165 W.

Upgrade paths

On the same socket the step up is a twelve core chip such as the Intel Core i9-9920X where thread count matters, keeping the board and DDR4. The 9900X keeps its place where higher ten core clocks beat more cores for mixed work.

Moving past LGA 2066 means a new board and usually DDR5 on current platforms. Owners usually add memory or a faster GPU before replacing the processor.