, , . , (2, 4 8 ) :
1) ACTIVATE;
2) READ;
3) , ;
4) PRECHARGE ( , , RD+AP).
RAS# CAS# (tRCD), CAS# (tCL). . , (2, 4 8), , 1 SDR, 2 DDR. tBL.
, SDRAM . PRECHARGE x , , ( , PRECHARGE READ , x). , , , CAS# (x = tCL 1).
, (tRP).
, ( ACTIVATE PRECHARGE, tRAS), , . :
tRAS, min = tRCD + tCL + (tBL (tCL 1)) 1,
tRCD , tCL , (tBL (tCL 1)) , , , tRAS , PRECHARGE. , :
tRAS, min = tRCD + tBL.
, , SDRAM, , tRAS (!) CAS#, tCL. , .
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, DDR (tCL-tRCD-tRP) 2-2-2. BL = 2 ( DDR) 1 . , tRAS 3 ( tRAS ). , 4 (BL = 4, tBL = 2), 4 , , 8- (BL = 8, tBL = 4) tRAS 6 . , , tRAS < 5, , (BL = 8, , BIOS ), tRAS , 6. BL = 4, tRAS= 5.
, 1- , tRC. , , , tRAS, , tRP, :
tRC = tRAS + tRP.
, (, AMD64) tRAS tRC, . , , tRAS, tRC ( ) .
, , : tCL-tRCD-tRP-tRAS, . (, 2-2-2-5 2.5-3-3-7 DDR; 3-3-3-9, 4-4-4-12 5-5-5-15 DDR2) .
, (, tRCD tCL, tRAS - ), , . , CAS# (tCL), , tRCD tRP ( , ).