Abit AT8: µGuru comes to the RD480

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Processor:	AMD Athlon 64 4000+ ( San Diego) AMD Opteron 170 ( Toledo)
CPU Voltage: AMD Athlon 64 4000+ AMD Opteron 170	1.5250V (1.4000V default) 1.4500V (1.3500V default)
Memory Settings:	2.5-3-3-7 1T - (12x) 2.5-3-3-7 1T - (10x)
Memory Voltage:	2.9V +.30mV
NB 1.2V Setting:	1.60V
HT Voltage:	1.35V
LDT Multiplier:	5x up to 250HTT, 4x up to 285HTT
Memory:	OCZ PC4800 Platinum Edition
Cooling:	Zalman CNPS9500
Power Supply:	OCZ Power Stream 520
Maximum CPU OverClock: (AMD Athlon 64 4000+)	256HTT x 12 (3072MHz) +28%
Maximum HTT OverClock: (AMD Athlon 64 4000+)	256HTT x 9 (2304MHz) +28%
Maximum CPU OverClock: (AMD Opteron 170)	285HTT x 10 (2850MHz) +42%
Maximum HTT OverClock: (AMD Opteron 170)	285HTT x 9 (2565MHz) +42%

Our 4000+ CPU posted excellent results in the stock multiplier overclocking test. The board is definitely a very good overclocker, but the issue with the 1.1 BIOS not allowing effective overclocking past the maximum HTT setting at stock multipliers is not acceptable. As an example we had no issue overclocking our AMD Athlon 64 4000+ to a 322 HTT setting at a 9x multiplier with the version 1.0 BIOS but could not reliably exceed a 256 HTT setting with the 1.1 BIOS. At these overclock settings, the system was able to complete all of our benchmark test suites three consecutive times and run Prime95 and SuperPI without issue. While the results do not match those of the AMD Athlon X2 based systems, the board produced top results in the 3DMark05 overclocking results for an AMD Athlon 64 CPU and X1900 CrossFire combination. In fact, this test combination exceeded our Asus A8R-MVP results by almost 400 3DMarks at similar settings.

Our Opteron 170 posted excellent results at the stock multiplier settings. However, this CPU has reached 2.95GHz on 1.450V in past testing. Once again, the issue with the 1.1 BIOS not allowing effective overclocking past the maximum HTT setting at stock multipliers is not acceptable. At the 10x285 overclock settings, the system was able to complete all of our benchmark test suites three consecutive times and run Prime95 and SuperPI without issue. Overall, the board would make an excellent platform for overclocking with BIOS corrections.


Memory Stress Testing

Memory stress tests look at the ability of the Abit AT8 to operate at the officially supported memory frequencies of DDR-400, at the best performing memory timings that the OCZ PC4800 Platinum Edition will support.

Abit AT8 Stable DDR-400 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
Command Rate:	1T
Voltage:	2.7V

The Abit AT8 was very stable with 2 DDR modules in Dual-Channel mode at the settings of 2-2-2-5 at 2.7V provided that we used the OCZ PC4800 memory and 1.1 BIOS. We will now install all four available memory slots, which will result in more strenuous requirements on the memory subsystem than testing 2 DDR modules on a motherboard.

Abit AT8 Stable DDR-400 Timings - 4 DIMMs (4/4 slots populated - 2 Dual-Channel Banks)
Clock Speed:	200MHz (800FSB)
CAS Latency:	2
RAS to CAS Delay:	2
RAS Precharge:	2
RAS Cycle Time:	7
Command Rate:	2T
Voltage:	2.8V

The Abit AT8 was very stable with 4 DDR modules in Dual-Channel operation at the settings of 2-2-2-7, but required the command rate to be increased to 2T along with a voltage increase to 2.8. Once again, we had to utilize our OCZ PC4800 memory and BIOS 1.1 in order to achieve these settings. Although other memory types were fully compatible, they required the 1.1 BIOS and memory settings adjusted to SPD values in the BIOS for one reboot sequence before changing the memory settings manually.