Manual para o xw4600 só lista PC2–5300E sem buffer (667 MHz) e DIMMs PC2–6400E (800 MHz) suportados:
Use only industry-standard, unbuffered, PC2–5300E (667 MHz) or PC2–6400E (800 MHz) DIMMs.
If multiple DIMMs are installed in a workstation, they must be installed in pairs of the same size and typein each channel.