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Modern DDR4 SDRAM can run up to 2133Mhz, but DDR SDRAM is designed to increase speed by taking advantage of CPU caches. For peak performance reads occur in batc
by sitharus 9y ago
Modern DDR4 SDRAM can run up to 2133Mhz, but DDR SDRAM is designed to increase speed by taking advantage of CPU caches. For peak performance reads occur in batches so one read command also fill the cache with nearby data.
SRAM can go fast since that’s what caches are made with, but that’s expensive. Also it would need to be close to the CPU as wire latency is non-trivial at high clock speeds.
- ZenoArrow 9y agoSomething I don't understand is why SRAM is more expensive than SDRAM. Is it just the manufacturing volumes and/or manufacturing yield, or are there architectural differences that make SRAM more expensive?
- cesarb 9y agoEach "bit" in SRAM is bigger than each "bit" in DRAM. Typical SRAM uses six transistors for each "bit", while typical DRAM uses one transistor and one capacitor. Bigger chips means less chips per wafer, and a larger chance for a chip to have a manufacturing defect.
- ZenoArrow 9y agoThank you for the explanation.