CPU Architecture and Performance
Cores and threads: a core is an independent processing unit within the CPU. Modern CPUs have 4–16+ cores. Hyper-threading (Intel) / SMT (AMD Simultaneous Multi-Threading): allows each physical core to handle two threads simultaneously — a 4-core CPU with hyper-threading appears as 8 logical processors to the OS. More cores/threads = better multi-tasking and multi-threaded workloads (video encoding, 3D rendering).
Clock speed (GHz): the number of instruction cycles per second — higher is generally faster for single-threaded tasks. Base clock: guaranteed operating speed. Boost clock: maximum short-burst speed when thermal and power headroom allow. Modern processors automatically boost. Example: Intel Core i7-13700K: base 3.4 GHz, boost 5.4 GHz.
Cache memory: small, fast memory built into the CPU. L1 cache: fastest, smallest (32–128 KB per core) — holds instructions and data being actively processed. L2 cache: medium (256 KB – 1 MB per core). L3 cache: largest (8–32+ MB, shared across cores) — much larger but slower. Cache reduces main RAM accesses, significantly improving performance. Cache misses (not found in cache) are the biggest CPU performance penalty.
Integrated graphics (iGPU): many CPUs include a built-in graphics processor. Allows a system to function without a discrete GPU. AMD: most Ryzen CPUs without 'G' suffix lack iGPU. Intel: most Core CPUs include Intel UHD/Iris Xe graphics. Useful for: office systems, budget builds, and as a fallback when a discrete GPU fails.
CPU Sockets, Cooling, and Power
Socket compatibility: the CPU socket must match — Intel uses LGA (Land Grid Array) sockets with pins on the motherboard: LGA1700 for 12th/13th gen Intel Core. AMD uses AM5 (LGA) for Ryzen 7000 series; AM4 (PGA) for Ryzen 3000/5000. Check CPU and motherboard socket type before purchase — incompatible sockets physically cannot mate. BIOS updates may be needed for newer CPUs in existing boards.
TDP (Thermal Design Power): the maximum heat the cooling system must be able to dissipate, measured in watts. 35W: laptop/low-power CPUs. 65W: standard desktop. 125W+: high-performance desktop. Cooling solution must match or exceed TDP. Stock coolers included with boxed CPUs are rated for the box CPU's TDP — high-end or overclocked CPUs require aftermarket cooling.
Cooling methods: Air cooling: heatsink (aluminum/copper fins) + fan. Thermal paste between CPU and heatsink fills microscopic gaps for better heat transfer — replace dried thermal paste on older systems. Liquid cooling (AIO — All-in-One): pump, radiator, fans — better for high TDP CPUs and overclocking. Passive cooling: no fan — used in silent/embedded systems with low TDP CPUs. Never operate a CPU without a heatsink — will overheat and throttle or fail within seconds.
Thermal throttling: when CPU temperature exceeds safe limits (typically 90–105°C), it reduces clock speed to lower heat output — performance drops dramatically. Symptoms: sudden slowdown under load, high temperatures in monitoring software. Fix: replace thermal paste, improve cooling, clean dust.