/ˈɛs ɡræm/
n. — “SGRAM: standard DRAM with graphics pretensions, strutting special features to handle pixel-pushing without total memory anarchy.”
SGRAM (Synchronous Graphics RAM) is specialized synchronous dynamic RAM incorporating graphics-specific features like block writes, write masks, and internal burst control to accelerate 2D/3D rendering pipelines on graphics hardware. Unlike vanilla SDRAM or system DDR, SGRAM embeds hardware support for filling screen blocks with uniform color (GPU block write), masking per-pixel writes during blending (write mask), and self-timed bursts that pretend random texture fetches don't murder bandwidth. Deployed as chips on graphics card PCBs, early GDDR generations evolved from SGRAM's playbook before outgrowing it with raw speed.
Key characteristics and concepts include:
- Block write mode painting entire 16/32/64-byte rectangles in one command, mocking pixel-by-pixel drudgery for GUI fills and clear operations.
- Write masking 1-4 bits per byte to enable alpha blending without read-modify-write hell, keeping compositing snappy on era-appropriate resolutions.
- Synchronous burst chains with programmable length/type (linear, wraparound) that coalesce texture loads into efficient sequences rather than scattershot pokes.
- Optional self-refresh and power-down modes pretending battery life matters on desktop behemoths, plus NOP commands for precise pipeline control.
In a classic rendering flow, SGRAM endures block clears for Z-buffer init, masked texture blits for transparency, and burst yanks for mipmapped surfaces—all orchestrated by the GPU to fake smooth frames on 2000s hardware before GDDR3 bandwidth buried the feature set.
An intuition anchor is to see SGRAM as DRAM with a graphics cheat sheet: not just dumb storage, but a co-processor whispering "fill this block, mask those bits" to dodge the inefficiencies of treating pixels like generic data slop.