Why DDR & DDR2 are not affected from rowhammer

[rokko]

Why DDR & DDR2 are not affected from rowhammer ?
or how can I test rowhammer memory of ddr2 ?

[David (PassMark)]

I don't know if they are totally immune, but the access speed and feature size of the silicon means that electrical interference between rows is less likely.

The existing row hammer test in MemTest86 works for DDR2 as well as DDR3 and DDR4.

[rokko]

DDR2 are tested without rowhammer by old version of memtest under Bios not EFI or am I wrong?
but I think most current DDR2 use same technology of DDR3 so maybe affected by same problem.

[David (PassMark)]

Yes, for V6 of the software you do need a UEFI based machine. And I agree there aren't going to many of those that support DDR2. And probably none that support the original DDR standard. There are hardware based RAM testers available, so maybe one of those can test the older RAM.