nForce4 Ultra Roundup: Charting the Mainstream

Abit Fatal1ty AN8: Overclocking and Stress Testing

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Abit Fatal1ty AN8
Processor:	Athlon 64 4000+ (2.4GHz, 1MB Cache)
CPU Voltage:	1.5375V (default 1.50V)
Cooling:	Thermaltake Silent Boost K8 Heatsink/Fan
Power Supply:	OCZ Power Stream 520W
Memory:	OCZ PC3200 EL Platinum Rev. 2 (Samsung TCCD Memory Chips)
Hard Drive:	Seagate 120GB 7200RPM SATA 8MB Cache
Maximum OC: (Standard Ratio)	234x12 (Auto HT, 2-3-3-7, 1T, 2.8V) 2808MHz (+17%)
Maximum FSB: (Lower Ratio)	250x11 (2750MHz) (4X HT, 2.5-3-3-7, 2.7V) (1:1 Memory, 1T, 2 DIMMs in DC mode) (+25% Bus Overclock)

Abit almost invented the concept of the overclocker's motherboard, so we have to wonder what went wrong in the design of the AN8. The board is OK at stock speed overclocking at 234, but several other boards in this roundup do better with the same CPU. The real disappointment, however, is 1:1 overclocking with a reduced CPU multiplier. No matter what we did, we could not coax the Fatal1ty AN8 above a 250 CPU clock setting. The DFI and Epox both handle 300 or better just fine, but the Abit has something holding it back.

Perhaps this can be corrected with a BIOS upgrade, since we also played a bit with asynchronous overclocking on the Abit with the new 433, 466, 500 ratios with Rev. E. The Abit reached around 280 in some of those setups, but 1:1 was much poorer. Until Abit is able to fix this issue with 1:1 overclocking, it should be clear that there are better choices for an nForce4 board if overclocking is your goal.

Memory Stress Test Results:

Memory stress tests look at the ability of the Abit An8 Fatal1ty to operate at the officially supported memory frequency, at the best performing memory timings that our standard OCZ PC3200 Platinum Rev. 2 will support. Memory stress testing was conducted by running 1:1 at DDR400 with 2 DIMM slots operating in Dual-Channel mode.

Stable DDR400 Timings - One Dual-Channel (2/4 DIMMs populated)
Clock Speed:	200MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	7T
Precharge Delay:	2T
Command Rate:	1T

The Abit was completely stable with 2 DDR modules in Dual-Channel at the settings of 2-2-2-7 at default voltage. All of the nF4 motherboards in this roundup were able to reach these fast timings with OCZ PC3200 Platinum Rev.2 memory.

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 populated)
Clock Speed:	200MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	7T
Precharge Delay:	2T
Command Rate:	2T

The Abit AN8 Fatal1ty was completely stable at 2-2-2-7 memory timings, but the Command Rate did need to be lowered to 2T. This is a function of the on-chip Athlon 64 memory controller. We also found that the new Rev. E chips with an updated memory controller required 2T for 4 DS DIMMs.