Optimizing Latencies
Both DDR3-2800 samples are rated at 12-14-14-36 timings, and all three DDR3-2400 samples are rated at 11-13-13-3. But both speeds have much more in common when it comes to the lowest stable latencies that provide optimal response times.
| Best Stable Timings | ||||
|---|---|---|---|---|
| Row 0 - Cell 0 | DDR3-1600 | DDR3-2133 | DDR3-2666 | DDR3-2800 |
| 2 x Adata XPG DDR3 AX3U2800W8G12-DGV | 7-8-8-15 | 9-11-10-18 | 12-13-13-24 | 12-14-13-27 |
| Corsair Vengeance Pro CMY32GX3M4A2800C12R | 7-8-7-15 | 9-10-10-18 | 11-13-12-21 | 12-13-13-24 |
| G.Skill Ripjaws X F3-2400C11Q-32GXM | 7-9-8-15 | 10-11-11-18 | N/A | N/A |
| Kingston HyperX Beast KHX24C11T3K4/32X | 7-8-8-15 | 9-11-10-18 | N/A | N/A |
| Patriot Viper 3 PV332G240C1QK | 7-8-7-15 | 10-11-10-18 | 12-13-12-21 | N/A |
Adata's XPG kit required a slightly higher tRAS (the fourth primary timing, above) setting than the other products when I configured it to operate at DDR3-2666. Lower frequencies paved the way for even lower tRAS numbers than the ones in my chart, but without any improvement in the benchmark results.
Corsair’s Vengeance Pro kit was also able to accommodate the lowest primary latencies. That could be important in the search for the absolute-fastest 32 GB kit.
Higher data rates show well in Sandra’s memory latency test, in spite of the absolute higher latency required to get there. That’s partly because latency is counted in cycles, and cycle time is the inverse of frequency.
