NVIDIA nForce4 SLI XE: Enthusiast Features on a Budget

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Processor:	Pentium 4 Smithfield LGA 775 840EE Dual Core 3.2GHz
CPU Voltage:	1.4750V (1.4000V default)
Memory Settings:	3-2-2-8 at 667MHz
Memory Voltage:	2.2V
SPP Voltage:	Default
FSB Voltage:	Default
Cooling:	Zalman CNPS 9500
Power Supply:	PC Power and Cooling 850 SSI
Maximum CPU OverClock:	254fsb x 17 (4318MHz) +35%
Maximum FSB OverClock:	268fsb x 16 (4288MHz) +34%

This board is a competitve overclocker when comparing it to the Intel 975X boards for maximum CPU speeds, but it still trails the 975X boards in FSB speeds as our Asus and Gigabyte boards can reach a 340FSB level for performance testing although their application stable FSB levels are slightly above 300. At these settings, the system is able to complete all of our benchmark test suites three consecutive times along with SuperPI and run Prime95 for a minimum of four hours. We lowered the CPU multiplier to 14, but it could not overclock past a 268FSB setting with our test CPU. We changed the LDT ratio to several different settings without success. These results continue the pattern that we see in the nForce4 Intel Edition chipsets not reaching high FSB speeds, yet being very successful in overclocking the CPU at standard FSB settings.

We installed our 955EE CPU and were able to reach the highest CPU overclock recorded for our sample unit. The board performed flawlessly at this setting, and reaching 4.62GHz on air with this chip is impressive. However, all attempts at lowering the multiplier and extending the bus speed past 1100Mhz resulted in failure within our benchmark test suite.

In limited SLI testing with our recently received EVGA 7900GTX card, the board posted excellent results in the synthetic and game benchmarks. The scores generated in the Pentium D category for 3DMark03 are class leading as of this writing.


Memory Stress Testing

This memory stress test looks at the ability of the ECS C19-A SLI to operate at the officially supported memory frequencies of 533MHz DDR2, at the best performing memory timings that the Corsair CM2X512A-5400UL revision 1.3 will support. Note that this memory is rated at 3-2-2-8 timings for 667MHz operation.

ECS C19-A SLI Stable DDR2-667 Timings - 2 DIMMs (2/4 slots populated - 1 Dual-Channel Bank)
Clock Speed:	200MHz (800FSB)
Timing Mode:	667MHz - Default
CAS Latency:	3
RAS to CAS Delay:	2
RAS Precharge:	2
RAS Cycle Time:	8
Command Rate:	1T
Voltage:	2.1V

The ECS C19-A SLI was very stable with 2 DDR2 modules in Dual-Channel at the settings of 3-2-2-8 at 2.1V. We will now install all four available memory slots that result in more strenuous requirements on the memory subsystem than testing 2 DDR2 modules on a motherboard.

ECS C19-A SLI Stable DDR2-667 Timings - 4 DIMMs (4/4 slots populated - 2 Dual-Channel Banks)
Clock Speed:	200MHz (800FSB)
Timing Mode:	667MHz - Default
CAS Latency:	3
RAS to CAS Delay:	3
RAS Precharge:	3
RAS Cycle Time:	8
Command Rate:	2T
Voltage:	2.1V

The ECS C19-A SLI was completely stable with 4 DDR2 modules in Dual-Channel operation at the settings of 3-3-3-8, but it required the command rate to be increased to 2T.