Rated FSB and Mobo FSB

Skeeter · 26 Jan 2008 at 01:38

Hi

Just wondered if anyone could clear things up for me a bit here. What is the link between your FSB, your Rated FSB in CPUz, and the FSB your mobo supports.

My CPU is oc'ed to 3.2Ghz with an FSB of 400 running thruugh an 8x multiplier for the cpu, and a 2x for the RAM (PC2-6400 at stock 800Mhz). This upping from 266 to 400 has pushed my Rated FSB in CPUz from 1066 to 1600. Now, my Mobo states it takes a 1066Mhz FSB, so what does this mean? What is a rated FSB, why or how is it running at 1600, and how does this fit with the talk that 965P mobos dont support the new E8xxx Intel CPUs as they have a 1333Mhz FSB... Im confused :confused:

Cheers

PCZ · 26 Jan 2008 at 03:35

Skeeter

I will try to explain

Rated FSB is the maximum that the chipset maker validates the Chipset for.
Officially there can be no support for 333Mhz [1333 Quad Pumped] FSB CPU's on your board.
You have an old chipset that was never intended to run at 333Mhz.

Reality is you can overclock the board by raising the FSB well above the Chipset spec.
400Mhz in your case which is 1600 Quad Pumped.

It works as there is massive headroom on Intel Chipsets.

Skeeter · 26 Jan 2008 at 17:35

So the FSB stated as being 1066 on my mobo is what is now actually running at 1600? Thats what I thought, but was confused by people stating 1333 doesnt work (Im not planning an E8xxx CPU, just wondered).

So this means that my CPU talks to my NB at 400MHz which then goes through some mystical quad speed boster which is seperate from the multipliers on both my CPU and RAM (8x and 2x respectively).

Computers, there oh so simple! lol

gurusan · 26 Jan 2008 at 17:36

yeah these dual data and quad data rates are so retarded IMO. There should just be 1 REAL rating (FSB clock)

pegasus1 · 27 Jan 2008 at 00:11

Same as people who state that you need 6400 ram for an E2180, that chip has a 10 multi so if you use a 333 fsb and the ram at stock (5400 speed) you will get 3.33ghz

PCZ · 27 Jan 2008 at 08:10

As you have correctly deduced your FSB is 400Mhz.
Quad pumped mumbo jumbo means it's 1600 quad pumped.

Quad Pumped Mumbo Jumbo
Data is transferred 4 times per clock cycle, twice on the rise and twice on the fall of the clock signal.

If you RAM is set to 1:1 that will be using the 400Mhz FSB clock.
RAM running at 400Mhz is known as DDR2 800.
Guess what its double pumped.

DDR means Double Data Rate.
Data can be read twice per clock signal.

The clock for the RAM is a multiple of the FSB.
You could for example have an FSB of 266Mhz and the RAM bus could be set 2:3 and run at 400Mhz.