The Twin 2X4096-6400C5 G is a 4096 M Byte matched pair of DDR2 SDRAM DIMMs. This part delivers outstanding performance in the latest generation of dual-channel DDR2-based motherboards. It has been tested extensively in multiple DDR2 motherboards to ensure compatibility & performance at its rated speed. This memory has been verified to operate at 800 M Hz at the low latencies of 5-5-5-18. Corsair’s line of 4GB memory kits are designed for PCs featuring 64-bit operating systems. Please note: Installing 4GB onto PCs with 32-bit operating systems is not advised since 32-bit operating systems do not support 4GB of system memory. 4096 Megabytes of DDR2 memory Two matched CM2X2048-6400C5 G modules Designed for 64-bit operating systems 100% tested at 800 M Hz in high performance DDR3 motherboards Legendary Corsair reliability & service Lifetime warranty Each module pair is tested together at 800 M Hz Tested & packaged in pairs Packaged together immediately following system test Tested at JEDEC standard latency settings (5-5-5-18) at 1.9V SPD programmed at: JEDEC standard 5-5-5-18 values at 800 M Hz Designed for 64-bit Operating Systems