Epox 9NDA3+: A New Socket 939

Memory Stress Testing: Epox 9NDA3+

The memory stress test is very basic. It simply tests the ability of the Epox 9NDA3+ to operate at its officially supported memory frequency (400MHz DDR) at the lowest memory timings OCZ PC3200 Platinum Rev. 2 modules will support. All DIMMs used for stress testing were 512MB double-sided (or double-bank) memory. Memory was only tested in Dual-Channel mode using either one dual-channel (2 DIMMs) or 2 dual-channels (4 DIMMs).

Stable DDR400 Timings - One Dual-Channel (2/4 DIMMs populated)
Clock Speed:	200MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	10T*
Precharge Delay:	2T
Command Rate:	1T

*Several memory tests have shown that memory performs fastest on the nVidia nForce chipsets at a TRas (RAS Precharge) settings in the 9 to 13 range. We ran our own Memory Bandwidth tests with memtest86 with TRas settings from 5 to 15 at a wide range of different memory speeds. The best bandwidth was consistently at 9 to 11 at every speed, with TRas 10 always in the best range at every speed. The performance improvement at TRas 10 was only 2 to 4% over TRas 5 and 6 depending on the speed, but the performance advantage was consistent across all tests. All benchmarks were run at a TRas setting of 10.

Using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-10 timings at 2.6V.

Stable DDR400 Timings - 2 DIMMs (2/4 DIMMs populated)
Clock Speed:	166MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	10T*
Precharge Delay:	2T
Command Rate:	2T

*Several memory tests have shown that memory performs fastest on the nVidia nForce chipsets at a TRas (RAS Precharge) settings in the 9 to 13 range. We ran our own Memory Bandwidth tests with memtest86 with TRas settings from 5 to 15 at a wide range of different memory speeds. The best bandwidth was consistently at 9 to 11 at every speed, with TRas 10 always in the best range at every speed. The performance improvement at TRas 10 was only 2 to 4% over TRas 5 and 6 depending on the speed, but the performance advantage was consistent across all tests. All benchmarks were run at a TRas setting of 10.

Tests with all four DIMM slots populated on the Epox board were something of a disappointment, however. Most 939 boards that we have tested require 2T Command Rate with 4 DIMMs in two dual channels. Not surprisingly, 2T was also required with 4 dimms on the 9NDA3+. However, this Epox is the only 939 board we have tested that absolutely forces DDR333 when four DIMMs are installed. Some other boards that we have tested also try to force DDR333 with 4 DIMMs, but this can normally be corrected to DDR400 by selecting that speed in BIOS. However, the Epox sets DDR333 with 4 DIMMs even if you specify DDR400. With no way to even try DDR400 with 4 DIMMs, we are left with the forced DDR333 setting with 4 dimms in our memory tests.

Epox can possibly correct this strange 4-DIMM memory behavior with a BIOS update. For now, if you absolutely need a 939 board that supports 4 DIMMs at DDR400, you will need to look at other 939 motherboards, since the Epox is the only 939 board that we have tested which cannot run at DDR400 with 4 DIMMs. Of course, we did not need to slow memory timings at all with 4 DIMMs, though we would hardly expect that with memory running at DDR333 instead of DDR400.