Well that Refresh Period is incorrect for that memory frequency. Asus bios don't always adjust it automatically properly or give manual adjustment. Refresh Period is 7.8uS, and tREF == ( tRFC[ns] * rows * banks ) / IO frequency
For 1GB dimms with 256Mbit memory chips, 4 banks , 16K rows and tRFC of 45 and DDR2-1066 which has IO frequency of 533.
tCK = 1000ns (1ms) / 533 (which is the bus clock of 1066) = 1.86ns
tRFC = 45 clocks = tCK * 45 clocks = 83.7ns.
so tREF for this would be:
( 83.7 * 16384 * 4 ) / 533 == 10291 clocks
Optimal Refresh period in clocks = closest value to 10291. Higher is always better.
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