Each cache consists of 2X upsized cells; the L2 and L3 are augmented with a SECDED code. Due to high sensitivity to additional latency in the L1 and high cost of per-byte ECC, the L1 implements byte parity which allows error detection but cannot repair failing bits. As depicted in Figure 6, the lack of ECC causes the Vmin of the L1 cache (700mV) to exceed that of the L2 and L3 caches, each of which can operate comfortably below 700mV. However, none of the arrays can operate below 600mV.