Intel Core i5-8420T socket: LGA 1151

What the Core i5-8420T is

The Core i5-8420T is a six core, six thread desktop processor with a 1.8 GHz base and up to 3.4 GHz turbo. It carries 9 MB of shared L3 cache and a 35 W TDP on the 14 nm process. The TechPowerUp database lists part number SR3X7 with a September 1, 2018 release.

The T suffix marks a low power bin for small towers where heat and noise matter more than sustained clocks. Six cores still cover office multitasking and light threaded loads, with turbo covering bursts. The multiplier is locked at 18 times the 100 MHz base clock.

UHD Graphics 630 covers office displays without a separate card. ECC is listed as not supported, so standard desktop DIMMs are the fit. The 35 W rating suits compact cases with modest airflow.

Socket and motherboard compatibility

The 8420T fits LGA 1151 revision 2 on 300 series motherboards such as H310, B360 and H370. Boards sold in late 2018 accept it with the shipping BIOS where the maker lists the part. The Socket vs chipset: what decides whether a CPU works guide explains the two revisions of this socket.

It does not fit 100 or 200 series boards, which are revision 1 for 6th and 7th Gen chips. Small towers gain the most from the T bin, since a 35 W chip stays quiet under office loads. Check the board CPU list for the exact T model before ordering.

Thin clients and living room PCs suit this SKU where a 65 W chip would run hot. A low profile cooler on the shared 75 mm pattern covers it easily. The Intel Core i5-8400T is a nearby 35 W six core with wider listings.

Memory, PCIe and cooling

Memory support is DDR4 in two channels at up to 2666 MT/s, with about 42.7 GB per sec of bandwidth. ECC is listed as not supported. Two matched sticks give dual channel speed for office multitasking across six cores.

PCI Express arrives as version 3.0 with 16 lanes from the CPU for graphics and storage. A single NVMe drive and a low profile card fit the lane budget of a compact tower. Cooling uses the shared 75 mm LGA 1151 pattern at 35 W, so small stock coolers cope well.

Upgrade paths

On the same socket the step up is the 65 W Intel Core i5-8400 where sustained clocks matter, keeping the board and DDR4. The 8420T keeps its place where quiet operation beats raw speed. A BIOS update may be needed when moving between T and non-T chips on older boards.

Moving past LGA 1151 to LGA 1200 needs a new board, since no 8th Gen chip fits the newer socket. Small tower owners usually add an SSD before replacing the processor.