Tech Glossary
Definitions for the technical terms used across TechCompare's calculators and comparisons. Each term links to the tool or comparison page where you can compute or explore it in detail.
Displays
PPI (Pixels Per Inch)
A measure of pixel density: the number of pixels per linear inch of a display. Higher PPI means smaller pixels and a sharper image, but only matters if you sit close enough to see the difference.
Open the tool →Retina distance
The minimum viewing distance at which the human eye can no longer resolve individual pixels, approximated as 3438 divided by the display's PPI. Sit further than this and the screen looks pixel-perfect.
Open the tool →Refresh rate (Hz)
How many times per second a display redraws its image, measured in Hertz. A 144Hz monitor refreshes 144 times per second, producing smoother motion than a 60Hz panel.
Open the tool →Display Stream Compression (DSC)
A visually lossless compression format standardized by VESA that cuts display bandwidth roughly 3:1, letting modern cables drive 4K 240Hz or 8K 60Hz over existing connectors.
Open the tool →Chroma subsampling (4:4:4, 4:2:2, 4:2:0)
A bandwidth-saving technique that reduces color resolution. 4:4:4 carries full color per pixel, 4:2:0 halves both horizontal and vertical color resolution, cutting bandwidth by about 50%.
Open the tool →Monitor curvature (1000R, 1500R, 1800R)
The radius in millimeters of a curved monitor's arc. A lower number means a tighter curve. 1000R matches the human eye's natural focal distance, 1800R is a gentler curve.
Open the tool →Memory
CAS Latency (CL)
The delay in clock cycles between a memory controller requesting a column of data and the RAM delivering it. Lower CL means less waiting, but true latency also depends on the clock speed.
Open the tool →True latency (ns)
The real-world delay of RAM in nanoseconds, calculated as (CL x 2000) / data rate. This is the only number that lets you compare kits across DDR3, DDR4, and DDR5 on equal footing.
Open the tool →MT/s (Megatransfers per second)
The data rate of DDR memory, measuring how many million data transfers happen per second. DDR5-6000 runs at 6000 MT/s, which is 3000 MHz internal clock due to double data rate.
Open the tool →JEDEC vs XMP/EXPO
JEDEC is the default conservative memory profile every DIMM boots with. XMP (Intel) and EXPO (AMD) are overclocking profiles stored on the DIMM that you enable in BIOS to unlock advertised speeds.
Open the tool →Storage
RAID 5
A RAID level using single distributed parity across N drives. Usable capacity is (N - 1) x drive size. It tolerates one drive failure and is the most common NAS configuration.
Open the tool →RAID 6
A RAID level using double distributed parity. Usable capacity is (N - 2) x drive size. It tolerates two simultaneous drive failures, making it safer for large arrays with long rebuild times.
Open the tool →RAID 10
A RAID level that mirrors then stripes data (RAID 1+0). Usable capacity is 50% of raw storage. It offers the best random-write performance of any RAID level and tolerates up to N/2 failures if they hit different mirror pairs.
Open the tool →Parity
Error-correcting data stored across drives in RAID 5 and 6. Parity lets the array rebuild lost data from a failed drive, but calculating it imposes a write penalty on every update.
Open the tool →Networking
CIDR notation
Classless Inter-Domain Routing notation, a shorthand for subnet masks. /24 means the first 24 bits are the network, leaving 8 bits for hosts. /24 gives 254 usable IPv4 addresses.
Open the tool →Subnet mask
A 32-bit number that divides an IP address into network and host portions. 255.255.255.0 is the mask for a /24 subnet, meaning the last octet is available for host addresses.
Open the tool →Broadcast address
The last IP address in an IPv4 subnet, used to send data to all devices on that network segment simultaneously. IPv6 has no broadcast, using multicast instead.
Open the tool →Gigabit Ethernet
A network standard carrying 1 billion bits per second (1000 Mbps, or about 125 MB/s in real-world file transfers). It is the most common wired networking speed in homes and small offices.
Open the tool →Developer
Cron expression
A 5-part scheduling string used by Unix cron, AWS EventBridge, and Kubernetes CronJobs. The fields are minute, hour, day of month, month, and day of week, read left to right.
Open the tool →Unix timestamp
The number of seconds since January 1, 1970 (the Unix epoch). It is the standard way to represent time in programming, and rolls over in the year 2038 problem on 32-bit systems.
Open the tool →Base64 encoding
A binary-to-text encoding that represents binary data as 64 printable ASCII characters. It is used to embed binary data in JSON, URLs, and email, expanding the size by about 33%.
Open the tool →JSON (JavaScript Object Notation)
A lightweight data-interchange format using human-readable text to store and transmit structured objects. It is the de facto standard for web APIs and configuration files.
Open the tool →Security
Entropy (passwords)
A measure of password unpredictability in bits. A 16-character password from a 90-character alphabet has about 104 bits of entropy, well beyond brute-force reach for modern hardware.
Open the tool →CSPRNG
Cryptographically Secure Pseudo-Random Number Generator. The browser's crypto.getRandomValues() is a CSPRNG backed by OS entropy, suitable for generating real passwords and API keys.
Open the tool →chmod (file permissions)
A Unix command that changes file permissions using octal notation (like 755) or symbolic notation (like rwxr-xr-x). The three digits apply to owner, group, and public respectively.
Open the tool →WCAG contrast ratio
A ratio measuring the luminance difference between foreground and background text, from 1:1 (no contrast) to 21:1 (max). WCAG AA requires 4.5:1 for normal text, AAA requires 7:1.
Open the tool →