Kingston KF556S40-16 2×16 GB vs Kingston ACR32D4U2S8HD-8X 2×8 GB
Short answer: which is best?
Kingston KF556S40-16 2×16 GB is 12.4 % stronger than Kingston ACR32D4U2S8HD-8X 2×8 GB. Kingston KF556S40-16 2×16 GB ranks #17 of 42 measured memory kits at WhatFPS (8,815 RAM score over 1 verified runs). Kingston ACR32D4U2S8HD-8X 2×8 GB ranks #24 of 42 measured memory kits at WhatFPS (7,843 RAM score over 1 verified runs). The numbers are measured in 2 verified WhatFPS runs — not estimated, not self-reported.
Measured comparison
| Metric | Kingston KF556S40-16 2×16 GB | Kingston ACR32D4U2S8HD-8X 2×8 GB |
|---|---|---|
| RAM score (the kit's own performance: bandwidth + latency) | 8,815 | 7,843 |
| Best rig (GAMING — whole PC) | 7,938 | 4,283 |
| Bandwidth, one thread | 27,859 MB/s | 19,145 MB/s |
| RAM latency (lower is better) | 95.4 ns | 82.8 ns |
| Rated speed | 5,600 MT/s | 3,200 MT/s |
| Runs at (seen, avg) | 5,600 MT/s | 2,933 MT/s |
| Capacity | 32 GB | 16 GB |
What the numbers mean
The RAM score is the kit's measured performance in the rigs it sat in — single-thread bandwidth and latency beyond L3. Platform, BIOS settings and whether XMP/EXPO was on all affect it. GAMING is the whole rig's score. We show both and never mix them.
All numbers come from our benchmark suite, the same test on every PC, written in Rust with no middleware. The methodology is open at https://whatfps.com/metodik
All measurements for Kingston KF556S40-16 2×16 GB · All measurements for Kingston ACR32D4U2S8HD-8X 2×8 GB