Q What is the effective RAM speed index?

A A desktop orientated measure of RAM speed that favours bandwidth over latency.

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Real world performance scales reasonably well with memory frequency (data throughput). The more data transferred per second the better. If two sets of memory have the same bandwidth (GB/s) then the better performing kit will have lower latency.

CPU Architecture Latency

Lower latency results in quicker data retrieval and faster computations. Multi socket server CPUs have much higher latency than single socket CPUs. In a multi socket configuration data often has to pass through an additional memory controller before arriving at its destination. Desktop architectures also exhibit different latency characteristics. The Zen CPU architecture has significantly higher latency than Skylake (70 vs 45 ns) which is partly why Skylake delivers superior gaming (fewer frame drops) and higher database throughput despite having comparable processing cores.

Effective RAM speed

The effective RAM speed index is weighted as 80% multi-core throughput, 10% single-core throughput and 10% latency. Dual channel RAM running at 3000 MHz on a skylake chip ≈ 100%. See a list of RAM Kits and their effective speeds (Avg. bench) here.