3 ms·
On my desktop (DH87RL / i7-4770 / 2x8GB Crucial DDR3L-1600), rowhammer_test reported errors after ~20 iterations (less than a minute). I went into the BIOS and
by p1mrx 12y ago
On my desktop (DH87RL / i7-4770 / 2x8GB Crucial DDR3L-1600), rowhammer_test reported errors after ~20 iterations (less than a minute).
I went into the BIOS and tried lowering the tREFI value from 6300 to 3150 (not sure what the units are). So far, it's gone 1000 iterations with no problems detected.
Edit: Actually, the units are probably multiples of the cycle time, just like CAS latency. So, for DDR3-1600, that would mean 6300x1.25ns=7.8μs, and 3150x1.25ns=3.9μs
http://en.wikipedia.org/wiki/CAS_latency http://en.wikipedia.org/wiki/CAS_latency
- thomasdullien 12y agoSingle-sided or double-sided hammering?
- p1mrx 12y agoI used rowhammer_test.cc, which I think is single-sided.
- throwaway41597 12y agoI tried and it reported one error under a second. I had to reboot because gcc started to make bash crash, it seems. Then I saw the README (duh!): Be careful not to run this test on machines that contain important data. On machines that are susceptible to the rowhammer problem, this test could cause bit flips that crash the machine, or worse, cause bit flips in data that gets written back to disc. **Warning #2:** If you find that a computer is susceptible to the rowhammer problem, you may want to avoid using it as a multi-user system. Bit flips caused by row hammering breach the CPU's memory protection. On a machine that is susceptible to the rowhammer problem, one process can corrupt pages used by other processes or by the kernel. (Mine is Kingston Hyper X 2x8GB DDR3 1600MHz)