Socket 939 Roundup: Battle at the Top

Asus A8V Deluxe: Overclocking and Stress Testing

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Processor:	Athlon 64 FX53 Socket 939 2.4GHz
CPU Voltage:	1.5V (default)
Cooling:	Thermaltake Silent Boost K8
Power Supply:	Antec TruePower 430W
Maximum OC: (Standard Ratios)	204 x 13 2652MHz (+10.5%)
Maximum FSB: (Lower Ratio)	289x9 (2601) at 1:1 Memory

The A8V Deluxe Revision 2 has come a long way from the first revision that didn't even have an AGP/PCI lock. Revision 2 is in a virtual dead heat with our top-performing MSI K8N Neo2 at 289 x9 with our Shikatronics DDR550 memory. The A8V also matched the highest OC with this FX53 at 204x13 at default voltage. This overclocking performance is as good as we are accustomed to seeing on the best nForce3 Ultra boards, and can only be called superb when achieved with the VIA K8T800 PRO, which is not always the best overclocker. To achieve this overclock level, we needed to reduce the base Hyper Transport frequency to 800.

Memory Stress Test Results:

The memory stress test measures the ability of the the Asus A8V Deluxe to operate at its officially supported memory frequency (400MHz DDR) at the best performing memory timings our Mushkin PC3500 Level 2 or OCZ PC3500 Platinum Ltd Modules will support. Memory stress testing was conducted by running RAM at 400MHz with 2 DIMM slots operating in Dual-Channel mode. The memory configuration of the Asus is the more standard setup with slots 1 and 3 are the first Dual Channel.

Stable DDR400 Timings - 2 DIMMs (2/4 DIMMs - 1 Dual-Channel Bank)
Clock Speed:	200MHz
Timing Mode:	N/A
CAS Latency:	2.0
Bank Interleave:	Enabled
RAS to CAS Delay:	3T
RAS Precharge:	10T*
Precharge Delay:	2T
Command Rate:	1T

*Several memory tests have shown that memory performs fastest on the nVidia nForce and VIA K8T800 chipsets at a TRas (RAS Precharge) setting 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 memory bandwidth 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. Since best performance was achieved at 2-2-2-10 timings, all Athlon 64 benchmarks were run at a TRas setting of 10.

The Asus K8V Deluxe Rev.2 was completely stable with 2 dimms in Dual-Channel at the settings of 2-2-3-10 at 2.6V default voltage with 1T command rate. This is very slightly slower than the timings than worked on other Socket 939 boards. While we could run the majority of benchmarks at 2-2-2 timings, there were a few that were not completely stable until we increased Ras-to-Cas delay to 3. It should be noted that the BH5 memory modules we used for testing are no longer available for purchase, but we have not yet established our standard memory for future testing. We will be using a new standard memory in future motherboard tests.

As we first found in our latest Socket 754 roundup, the Command Rate is very important for top performance on a VIA chipset motherboard. The best performance is at a Command Rate of 1T, and the Asus A8V was completely stable at a 1T setting with 2 dimms. We set 'Bank Interleave' to 'Enabled' in the BIOS, and Sandra 2004 SP2 reported a 2-way Bank Interleave was being used by the memory controller. With an on-CPU memory controller with Athlon 64, this is not as important a setting as it is on with chipset-based memory controllers.

Filling all four available memory slots is more strenuous on the memory subsystem than testing 2 DIMMs on a motherboard.

Stable DDR400 Timings - 4 DIMMs (4/4 DIMMs - 2 Dual-Channel Banks)
Clock Speed:	200MHz
Timing Mode:	N/A
CAS Latency:	2.0
Bank Interleave:	Enabled
RAS to CAS Delay:	2T
RAS Precharge:	10T*
Precharge Delay:	2T
Command Rate:	2T

We see a very interesting result with all 4 dimm banks filled. The Asus A8V was able to run with all 4 dimm slots at more aggressive 2-2-2-10 settings than the 2-2-3-10 required for 2 dimms. Please keep in mind, though, that the Command Rate must be reduced to 2T when filling both Dual Channels, and the memory is actually a bit slower even though the other timings are slightly faster. The A8V Deluxe is also very picky about the settings that are used with 4 dimms in the 'Enable 2T' option in BIOS. If an Auto setting is used with 4 dimms the board tries to set 1T and single channel memory at a lower memory speed. If 'Auto' is selected and memory timings are forced to DDR400 the board would not boot. With 4 dimms, you will need to set the 2T option to 'Enable 2T' for proper Dual-Channel operation at DDR400.