5 ms·
ECC slows down RAM however RAM speeds are starting to become bounded by error rates. To push into the faster timings ECC actually becomes essential to keep the
by jacoblambda 6y ago
ECC slows down RAM however RAM speeds are starting to become bounded by error rates. To push into the faster timings ECC actually becomes essential to keep the system from becoming unstable.
This is the reason why DDR5 is so much faster despite using ECC effectively by default.
- wtallis 6y agoFor GPUs, it's not just the RAM timings and clock speeds that matter. The way they implement ECC also directly subtracts from the effective memory bus width and therefore the total bandwidth.
- jacoblambda 6y agoThis is true for off-die ECC (i.e the kind that computes ECC between chips using a separate chip) however on-die ECC (the ECC logic and parity memory being included in the memory chip itself) like what DDR5 will have doesn't have this bandwidth issue. It causes the dies to cost slightly more but otherwise largely results in the same performance as non-ECC memory. In the GPU space, this is why HBM2 memory doesn't really have a performance difference between ECC and non-ECC memory.