CPU

Updated: 2021-02-21

Intel or AMD

Only 2 brands to consider if you want to build or buy a PC. Previously Intel was the clear leader, though AMD's Ryzen series make it comparable with Intel in terms of performance.

AMD has successfully moved to 7nm since Zen 2 architecture, while Intel is still at 10 or 14 nm as of 2020.

AMD tends to have more cores and threads than Intel.

The product lines are well aligned:

  • entry level: Intel CORE i3, AMD Ryzen 3
  • mid level: Intel CORE i5, AMD Ryzen 5
  • high end: Intel CORE i7, AMD Ryzen 7
  • top level: Intel CORE i9, AMD Ryzen 9

Intel

Naming scheme:

  • categry: the first part of the name, Core i7-8700 is Core i7
  • generation: the first digit of the second part, e.g. Core i7-8700 is 8th Gen, Core i9-10900K is 10th Gen
  • codes:

    • K: unlocked for overclocking (AMD Ryzen processors are almost all unlocked by default)
    • F: no integrated GPU
    • E: embedded
    • T: low power

Integrated graphics:

  • Intel Iris Xe: introduced in 11th gen (Tiger Lake)
  • Intel UHD Graphics: the "old" integrated graphics

Intel Desktop CPU Generations Comparison:

Gen CPU Family Process Cores TDPs Chipset Platform Memory PCIe Launch
2nd Gen Sandy Bridge 32nm 4/8 35-95W 6-Series LGA 1155 DDR3 PCIe 2.0 2011
3rd Gen Ivy Bridge 22nm 4/8 35-77W 7-Series LGA 1155 DDR3 PCIe 3.0 2012
4th Gen Haswell 22nm 4/8 35-84W 8-Series LGA 1150 DDR3 PCIe 3.0 2013
5th Gen Broadwell 14nm 4/8 65-65W 9-Series LGA 1150 DDR3 PCIe 3.0 2015
6th Gen Skylake 14nm 4/8 35-91W 100-Series LGA 1151 DDR4 PCIe 3.0 2015
7th Gen Kaby Lake 14nm 4/8 35-91W 200-Series LGA 1151 DDR4 PCIe 3.0 2017
8th Gen Coffee Lake 14nm 6/12 35-95W 300-Series LGA 1151 DDR4 PCIe 3.0 2017
9th Gen Coffee Lake 14nm 8/16 35-95W 300-Series LGA 1151 DDR4 PCIe 3.0 2018
10th Gen Comet Lake 14nm 10/20 35-125W 400-Series LGA 1200 DDR4 PCIe 3.0 2020
11th Gen Rocket Lake 14nm 8/16 TBA 500-Series LGA 1200 DDR4 PCIe 4.0 2021

AMD

Naming scheme:

  • category: the first part of the name, e.g. Ryzen 5
  • generation: same as Intel, the first digit of the second part, e.g. Ryzen 5 2600 is 2nd Gen
  • codes:

    • X: higher stock clock speed

Zen Architecture:

  • Zen 2: 7nm. powering the 3-rd gen of Ryzen processors (Ryzen 3000 and Threadripper 3000)
  • Zen 3: since 2020; using the same 7nm process as Zen 2. The last microarchitecture before switches to DDR5 and new sockets.

Specs

Clock Speed

measured in GHz, the higher the faster. Most of mainstream modern CPUs are below 4 GHz, and this speed is NOT increase year over year. Instead new generations of CPUs focus on adding more cores and being more efficient.

"Overclocking" is to increase this speed beyond the spec. Intel chips with "K" and almost all AMD chips can overclock.

Instructions Per Cycle (IPC)

The average number of instructions executed for each clock cycle. It depends on CPU architecture.

Cores and Threads

Cores is the number of processors. Each core may have one or multiple threads ("multithreading"). E.g. some CPU spec says "6 Cores / 12 Threads".

Cache

Cache on chip. If the data needed by CPU can be found in Cache, it saves a trip to RAM.

3 layers: L1, L2, and L3. L1 is the fastest and smallest, L3 is largest while slower than L1 and L2, but still faster than RAM.

Thermal design power (TDP)

Measured in watts (W), assuming not overclocking. The mainstream is 65W / 95W, and higher for high end CPUs. Your choice of PSU (Power Supply Unit) and CPU cooler should depend on this.

Socket

It should match the socket on motherboard.

Others

  • PCIe Version
  • Max Boost