Why don't Intel Core cpus have FSB dividers for the RAM?

[Deleted member 4644]

My old 939 AMD allows me to run the CPU at say a 220 mhz clock, but I can "divide" the RAM clock and run it at say, 190mhz.

Is this possible on the newer Intel chips? If not, why not.

I understand that the multiplier is locked, but why not at least allow a FSB divider.

 

[ViRGE]

They do have dividers, they're called memory ratios. For example my Q6600 @ 3ghz(9x333) runs at a memory ratio of 1.2:1, allowing me to run my RAM at 400mhz.

Edit: This is a function of the memory controller in the Northbridge however, not the CPU itself

 

[Deleted member 4644]

Yea.. the person who told me otherwise must have been wrong! I just found the "unlink" think in the 680i manual.

Thanks.

 

[KIAman]

The unlink memory option is only for the Nvidia Chipsets. Using the dividers on the Nvidia chipset will only increase memory speed relative to FSB.

No intel chipsets for C2D have memory unlink feature. The memory only has one way to go and that is up.

ViRGE's example is FSB 333 and ratio of 1.2:1 (bios will say 6:5) allows the memory to be 400mhz (1.2) to 333mhz FSB (1)

As to why Intel Chipsets do not have that "unlink" feature, my best guess is that memory is plenty fast these days and the average C2D can be clocked pretty high without raising FSB too high. Keeping a 1:1 ratio might underclock some performance memory so the dividers are there to run the memory at their high spec frequency while not forcing the CPU to go so high.

For the newest chipset and ram (DDR3) the ram frequency is up to 2000mhz but the motherboard still needs to run the CPU at its rated FSB. The dividers help to run the ram spec without auto-overclocking the cpu in the process.