ASUS A8N-SLI Premium: Overclocking

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Processor:	Athlon 64, 4000+, San Diego Core
CPU Voltage:	1.5125V (1.4000V default)
Memory:	OCZ PC4800 Platinum Edition
Memory Voltage:	2.95
Cooling:	AMD Stock Heat sink and Fan
Power Supply:	OCZ Power Stream 520
Maximum CPU Overclock Standard Ratio (12)	255fsb x 12, 5x HT, (2.5-4-4-10, 1T) 3064MHz (+27%)
Maximum FSB Overclock Lowered Ratio (9)	295fsb x 9, 4x HT, (2.5-4-4-10, 1T) 2661MHz (+47.5% Bus Overclock)

This board is a good overclocker at the standard ratio, but we could not break the 300fsb mark with a 1:1 memory ratio. We had to run the standard memory timings, although performance was still excellent at these settings. The board just would not overclock well with the CAS Latency set at 2 (1:1 memory timings), but it did not have issues with the HT running near 1200. We tried relaxing the memory timings, reducing the HT settings to 3x, and increased voltages to the maximum allowed, but we could not increase the fsb past 295 while completing our benchmark suite. We were able to overclock the fsb to 340 at the 9x multiplier, which resulted in CPU operation of 3066MHz, but we had to reduce the memory ratios to reach this level. The test system was able to boot into Windows at a setting of 350fsb x 9, but was not stable enough to complete our testing. At the settings listed, our test system was able to complete the entire benchmark suite three times without any reported issues.

Memory Stress Testing

Memory stress tests look at the ability of the Asus A8N-SLI Premium to operate at the officially supported memory frequencies of 400MHz DDR, at the best performing memory timings that the OCZ Technology PC4800 Elite Platinum could support. The default setting for Command Rate in the Asus BIOS is 2T. You need to set Command Rate manually to 1T for best performance with 2 DIMMs in Dual Channel mode.

Asus A8N-SLI Premium Stable DDR400 Timings - 2 DIMMs (2/4 slots populated - 1 Dual-Channel Bank)
Clock Speed:	200MHz
CAS Latency:	2
RAS to CAS Delay:	2
RAS Precharge:	2
RAS Cycle Time:	5
Voltage:	2.8V
Command Rate:	1T

The Asus A8N-SLI Premium was completely stable with 2 DDR modules in Dual-Channel at the settings of 2-2-2-5 at the default 2.8V.

Tests with 4 double-sided DIMMs on an AMD Athlon 64 system are very demanding, since AMD specifies DDR333 for this combination. However, most AMD Athlon 64 motherboards combined with recent AMD processors have been able to handle 4 DIMMs at DDR400 settings.

Asus A8N-SLI Premium Stable DDR400 Timings - 4 DIMMs (4/4 slots populated - 2 Dual-Channel Banks)
Clock Speed:	200MHz
CAS Latency:	2
RAS to CAS Delay:	2
RAS Precharge:	2
RAS Cycle Time:	7
Voltage:	2.8V
Command Rate:	2T

The Asus A8N-SLI Premium was completely stable with 4 DDR modules in Dual-Channel at the settings of 2-2-2-7 at the default 2.8V.