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Should RAM not be faster than CPU front bus speed?

  • Memory
  • CPUs
  • Bus Speed
Last response: in Memory
August 27, 2009 12:23:10 AM

Is it true that your memory speed cannot run any faster than your processor's front bus speed? I have a q6600 with a fsb of 1066. Consequently, would any RAM faster than 1066 not do me any good. I was thinking of going to a new motherboard so that I can overclock my cpu. I was going to get DDR3 1600 but I don't want to mess with it if I won't see any speed improvements over slower DDR2. I know there is a lot of debate about DDR3 not being worth the money. That is not my issue. I just want to know if I will see better speeds from the 1600 mem or should I just use 1066 mem because of my cpu.

More about : ram faster cpu front bus speed

August 27, 2009 2:03:38 AM

When using DMA - Direct Memory Access - you can run the speed of the memory. Hard drives will use DMA quite often as do other components.
August 27, 2009 2:22:45 AM

So say my FSB is set at 340MHz, which makes my processor's FSB 1360MHz. My RAM is 800MHz but if I just have a 1:1 ratio with FSB to RAM the RAM is only running at.. you guessed it 680MHz. If I understand what you are saying, then if I set to to 800 (or higher if I want to overclock it) DMA is going to allow a performance increase. Without DMA however the RAM would be bottle-necked by the FSB. Is that right?

Additionally, how do you know if the motherboard/ram/whatever supports DMA for the RAM? Do you have to specifically enable it?
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September 22, 2010 8:27:19 AM

reading & Writing to ram should at a 1:1 ratio for best performans if the ram is faster then the CPU BUS not northbirdg's FSB then the ram's READ takes a performance hit if the CPU's BUS speed is faster then the ram it's Write takes a performance hit.
Read \1:2 2:3 3:4 - 1:1 - 2:1 3:2 4:3/ Write
its very simple

if you have a 1333MHz FSB your CPU bus would be about 333.2MHz x 4 plus or minus 1 to 4 MHZ your ram needs to be DDR2 667 LOL should be DDR2 666\2 = 333MHz for a 1:1 R\W ratio

if you have a 1600MHz FSB then your CPU bus is 400MHz x 4 your ram needs to be DDR2 800 or 400MHz x 2 for double data rate for a 1:1 R\W ratio

Your FSB or Front Side Bus is your north bridge Chip AKA Intel P35/\P45 chipset which can hit your rams top speed but that only gives the other hardware like the PCI & PCIe SATA, VIDEO, ect A HI SPEED access to the ram which is already very fast.
So for the best performance your better off matching the rams speed with the CPU's BUS to give the PC's Software a well Balanced Read \ Write to the Catch
September 22, 2010 8:27:55 AM

New Be I posted this late for Late people thanks