Hivatalos IBM HS21 Product Guide szerint
The HS21 supports up to 32GB of 667MHz PC2-5300 Fully BufferedECC (Error Checking and Correcting) double data rate II (DDR2) memory in 8 DIMMslots, using the Memory and I/O Expansion Unit, with optional Chipkill™ protection, for high performance and reliability. The base HS21 is packaged as a single-wide (30mm) blade and supports up to 16GBof memory in 4 DIMM slots.