915 Motherboard Roundup: Socket 775 for the Rest of Us

Abit AG8: Overclocking and Stress Testing

FSB Overclocking Results

Intel has recently talked about Speedstep, which is the ability of Prescott processors to run at both stock speed and a lower 14X multiplier. Speedstep works on most 925X motherboards and it has recently been added to some 915 motherboards with BIOS updates. This capability will likely be added to other 915/925X motherboards in the future. For that reason, all overclocking tests were performed at a stock 3.6GHz (18X) on motherboards in this roundup and at 14X, the Speedstep multiplier.

Front Side Bus Overclocking Testbed
Processor:	Pentium 4 Prescott LGA 775 560 ES (2.8GHz-3.6GHz)
CPU Voltage:	1.425V (1.3675V default)
Cooling:	Thermaltake Jungle 502
Power Supply:	OCZ Power Stream 520
Maximum CPU OverClock:	222x18 (3996MHz) +11%
Maximum FSB OC:	261FSBx14 (+31%)

The results of the Abit overclocks look impressive until you compare them to boards like the DFI, Asus, or MSI. It is fair to say that overclocking with the Abit AG8 is above average, but not the top of the roundup. The 261 wall is similar to the issues that we found with SATA drives on the Asus AA8 - you run into a wall with SATA around 260 on the Abit and you just can't break around it. The Abit AG8 will go higher in overclocking if you plan to use it with an IDE drive, but this can prove to be a challenge with just one IDE connector available for all your optical drives and a hard drive.

The AG8 was able to achieve a FSB of 261, a 31% overclock, with an ATI X800 XT and SATA hard drive. Abit manipulates the PCIe frequency with uGuru during boot to achieve higher overclocks. For more information on how Abit manages to overclock the AA8/AG8, please check Breaking Intel's Overclock Lock: The REAL Story.

Memory Stress Test Results:

The memory stress test measures the ability of the Abit AG8 to operate at its officially supported memory frequency (400MHz DDR) at the best performing memory timings that OCZ PC3200 Platinum Rev. 2 will support. Memory stress testing was conducted by running the DDR400 with 2 DIMM slots operating in Dual-Channel mode.

Stable DDR400 Timings - 2 DIMMs (2/4 DIMMs - 1 Dual-Channel Bank)
Clock Speed:	200MHz
Timing Mode:	1:1 (200:200 - Default)
CAS Latency:	2.0
Bank Interleave:	Auto
RAS to CAS Delay:	2
RAS Precharge:	2
Cycle Time (tRAS):	5

The Abit AA8 DuraMAX was completely stable with 2 DIMMs in Dual-Channel at the DDR settings of 2-2-2-5, at 2.6V default voltage.

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

Stable DDR400 Timings - 4 DIMMs (4/4 DIMMs - 2 Dual-Channel Banks)
Clock Speed:	200MHz
Timing Mode:	1:1 (200:200 - Default)
CAS Latency:	2.0
Bank Interleave:	Auto
RAS to CAS Delay:	2
RAS Precharge:	2
Cycle Time (tRAS):	5

The Abit uses familiar DDR memory and performed much as we have come to expect with 4 DDR400 DIMMs. With 4 DIMMs, the Abit was stable at the same aggressive 2-2-2-5 timings that we found with 2 DIMMs.