Searching for the Memory Holy Grail: Part 1
by Wesley Fink on July 27, 2003 11:13 PM EST- Posted in
- Memory
FSB Overclocking with 1, 2, and 4 DIMMs
Since we have established that the best performance at DDR400 or above (1:1) is with four DIMMs, it is natural to ask whether there is a downside to running four DIMMs instead of two or even one DIMM.| Front Side Bus Overclocking Test Setup | ||
| Processor: | Intel Pentium4 3.0C 800FSB Hyperthreading | Intel Pentium4 2.6C 800FSB Hyperthreading |
| Motherboard: | DFI 875PRO Lan Party(875) | Asus P4P800 Deluxe (865) |
| CPU Vcore: | 1.60v | 1.650V |
| Memory: | OCZ3700 GOLD DDR466 | OCZ3700 GOLD DDR466 |
| vDIMM: | 1.70V (MB limited) | 1.85V (MB Limited) |
| Cooling: | Thermalright SLK-900U | CoolerMaster HeatPipe |
| Power Supply: | Vantec 520W | Powmax 400W |
| Pentium4 3.0C 800FSB CPU | Pentium4 2.6C 800FSB CPU | |||||
| # of DS DIMMs: | 1 | 2 | 4 | 1 | 2 | 4 |
| MAXIMUM Stable FSB: | 992 (4x248) CPU Limited |
992 (4x248) CPU Limited |
968 (4x242) | 1048 (4x262) | 1032 (4x258) | 1024 (4x256) |
| SPD or Manual: | SPD | SPD | SPD | SPD | SPD | SPD |
| CAS Latency: | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 |
| RAS to CAS Delay: | 3 | 3 | 3 | 4 | 4 | 4 |
| RAS Precharge: | 7 | 7 | 7 | 7 | 7 | 7 |
| Precharge Delay: | 3 | 3 | 3 | 4 | 4 | 4 |
Despite the slightly lower overclock possible with four DIMMs, the best 1:1 performance is still with four DIMMs. For example, DDR516 using four DIMMs out-performs DDR530 with two DIMMs – since the four DIMMs are about 7% to 10% higher in UNBuffered memory performance.
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Anonymous User - Monday, July 28, 2003 - link
Great article. Pity Im too late. Is single sided RAM the same as single bank (electronic) or physically the ram chips are on a single side of the stick. Mushkin in particular are wary of using the single side term. Also What about PAT acceleration in conjunction with lower latency RAM and DIMM number? Some reviews have shown lower FSB with tight timings RAM and PAT acceleration beating looser timings 1:1 higher FSB RAM systems. Ah questions questions?pakuens - Monday, July 28, 2003 - link
Good article. I'm right in the middle of buying memory and it answered several questions. It saved me from an expensive mistake, as I was considering using two matched pairs, but of differing size.I like the unbuffered benchmark method.