Crucial Ballistix DDR2-800 PC2-6400

Performance:

With rated DDR2-800 speeds, and wishing to push the RAM to its limits, we turned to one of our i955X (Glenwood) solutions: Abit's AW8. This motherboard sports the i955X Chipset with an ICH-7R Southbridge and in the past we've been able to push this motherboard quite far with a Pentium D processor on air-cooling. Below is the complete list of the hardware and software powering this system.

For testing today, we ran the Crucial Ballistix DDR2-800 2 x 512MB modules with the specifications listed below. To compare the Ballistix DDR2-800, we also ran 2 x 512MB of Corsair's popular XMS2 PC2-5400UL DDR2-667 memory modules that are known for their extremely tight latencies at stock speeds and abilities to clock quite far (beyond 1GHz) with their memory frequencies. For comparative purposes, Corsair's stock settings were ignored and we ran these sticks identical to that of Crucial's. The memory ICs used on the XMS2 PC2-5400UL are actually manufactured by Micron and their popular "Fat Body" D9 IC's, which tend to perform greatly in an overclocking environment especially once Corsair sorts through them.

CRUCIAL PC2-6400: 204 x 14 = 2856MHz 3:5 DDR2-680 - 3-3-3-8 - 1.90V
CRUCIAL PC2-6400: 240 x 14 = 3360MHz 3:5 DDR2-800 - 4-4-4-12 - 2.10V
CORSAIR PC2-5400UL: 204 x 14 = 2856MHz 3:5 DDR2-680 - 3-3-3-8 - 1.90V
CORSAIR PC2-5400UL: 240 x 14 = 3360MHz 3:5 DDR2-800 - 4-4-4-12 - 2.10V

To some dismay, in our overclocking we didn't find these Crucial DDR2-800 modules to have much overclocking headroom. No matter the voltage supplied, FSB:DRAM ratio, or timings, we weren't able to push the RAM much further than about DDR2-820 speeds. Pushing the RAM much further than its rated speeds resulted in many instances of memory errors and the system failing to POST. We believe the system wasn't at blame due to excellent overclocking results we've experienced with other DDR2 modules in the past. In addition, we flashed to Abit's latest official BIOS release for the Abit AW8, release 14 (2005-10-18), which offers improved DRAM compatibility and CPU micro-code updates but we continued to reach a barrier when overclocking. To test the system memory stability we used memtest86+ v1.60. For benchmarking purposes, we used our usual Doom 3, LAME Compilation, LAME Encoding, FreeBench, and RAMspeed. In addition, we brought fourth Quake 4 into our arsenal of memory benchmarks to represent real-world performance under Linux.