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Is my FSB 800MHz or 1066MHz

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  • CPUs
  • DDR2
  • Intel
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October 19, 2007 2:02:33 AM

Intel Core 2 Duo E6600
Crucial Ballistix 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
ASUS P5B Deluxe LGA 775 Intel P965

I'm confused. Should I be running at 800MHz or 1066Mhz FSB? Or is that my memory speed and not my FSB?

More about : fsb 800mhz 1066mhz

October 19, 2007 2:05:06 AM

ETA: My memory says it is DDR2 800 (PC2 6400).
But my motherboard says FSB of 1066/800MHz.
And my CPU says FSB of 1066MHz.

So which am I (or should I be) running my FSB at?
Anonymous
October 19, 2007 2:53:55 AM

Your cpu saying it is at a 1066MHz FSB is what it should be at. That is normal/correct/stock setting. Your motherboard saying FSB of 1066/800MHz, is that in the specs, or in the bios? I assume that's the FSB processor support for your motherboard. Your memory speed is separate of the processor speed but it is good to run at a 1:1 ratio. Since your memory is DDR2 you could underclock it to 533 and you would still have a 1:1 ratio for FSB to memory speed(533*2 = 1066).
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October 19, 2007 3:05:35 AM

and at 533 you can tighten the ram timings too....
October 19, 2007 3:06:13 AM

if you have to ask "what's my fsb?" don't worry about 1:1 ratio, the gain in performance is marginal anyway.

For more details on your rig specs download and run cpu-z, a great informational tool: http://www.cpuid.com/cpuz.php
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October 19, 2007 3:48:21 AM

I wonder what would perform better: DDR2-800 at stock timings @800MHz or tightened timings at 533MHz (1:1). Somebody needs to test it. Without tightening the timings the 800MHz speed would win for sure, but if you tightened the timings it could get interesting.
October 19, 2007 3:51:24 AM

what would be the point of underclocking ram if he can overclock fsb :) 
October 19, 2007 4:50:41 AM

Ha ha! My thoughts exactly... E6600's overclock with the best of them... :sol: 
October 19, 2007 6:59:10 AM

E4000 series are allendale with rated FSB of 800.
E6000 series are conroe with rated FSB of 1066.

To better understand the numbers, it is a bus that is quad pumped:

800 / 4 = 200mhz x (mulitplier) = CPU speed

I have an E4400, so using that above to understand the stock speed:

800 / 4 = 200 x 10 = 2ghz or 2000mhz

Now the advertise speed off DDR2 memory makes it more confusing to understand.

DDR2 800 is actually way faster then needed for my E4400 to run. If I ran it at it's advertised speed, my cpu speed would be 4ghz. To understand the rated fsb of DDR2 800:

800 / 2 (double rated memory) = 400mhz (base speed)
400 x 4 = 1.6ghz or rated fsb 1600mhz

To understand my over clock by the numbers, I use DDR2 800, but currently run it slower:

280 x 10 = 2.8ghz or 2800mhz (way below 400mhz)

rated fsb:
280 x 4 = 1120mhz

Why did I buy DDR2 800 memory? For plenty of head room for OC, prices are cheap ($90 with $30 rebate on what I brought) and the possiblity of upgrading to the Q6600 later on. :D 

And last but not least, DDR2 533 memory is bascially all you need if you were to run any conroe core at stock. Looking at the numbers:

533 / 2 = 266.5
266.5 x 4 = 1066mhz (rated fsb)
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October 19, 2007 8:37:01 AM

Grimmy said:
E4000 series are allendale with rated FSB of 800.
E6000 series are conroe with rated FSB of 1066.

To better understand the numbers, it is a bus that is quad pumped:

800 / 4 = 200mhz x (mulitplier) = CPU speed

I have an E4400, so using that above to understand the stock speed:

800 / 4 = 200 x 10 = 2ghz or 2000mhz

Now the advertise speed off DDR2 memory makes it more confusing to understand.

DDR2 800 is actually way faster then needed for my E4400 to run. If I ran it at it's advertised speed, my cpu speed would be 4ghz. To understand the rated fsb of DDR2 800:

800 / 2 (double rated memory) = 400mhz (base speed)
400 x 4 = 1.6ghz or rated fsb 1600mhz

To understand my over clock by the numbers, I use DDR2 800, but currently run it slower:

280 x 10 = 2.8ghz or 2800mhz (way below 400mhz)

rated fsb:
280 x 4 = 1120mhz

Why did I buy DDR2 800 memory? For plenty of head room for OC, prices are cheap ($90 with $30 rebate on what I brought) and the possiblity of upgrading to the Q6600 later on. :D 

And last but not least, DDR2 533 memory is bascially all you need if you were to run any conroe core at stock. Looking at the numbers:

533 / 2 = 266.5
266.5 x 4 = 1066mhz (rated fsb)


and any 6xxx series with 50 at the end (6550, 6750, 6850) have FSB1333 or 333mhz x 4 = 1333mhz
October 19, 2007 11:04:33 AM

Hehe..

:oops:  . o O (I weally was going to add that, but got side tracked :lol: )
October 20, 2007 5:28:05 AM

Is the Kentsfield the same as the Conroe as far as FSB and the way you do the calculations?
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October 20, 2007 5:36:29 AM

yes....the fsb works the same....

Kentsfield is just 2 conroes put in one substrate(they are not attached in 1 die....its 2 dual cores(each on there own die) under the heat spreader)



Look ma' dual dual core
October 20, 2007 7:20:53 AM

So would DDR2-1066 be way overkill for a Q6600 CPU?
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October 20, 2007 7:54:56 AM

short answer....yes, the cpu runs stock 533 and not many push them past 3.6. That would be DDR2 800.

By the same right...there is no such thing as overkill....if you want it...get it....you can run out of sync and use it to its full 1066 fsb is you want(there will be almost no noticeable improvements tho :(  )

Or

you can get it and run it as lower speeds with tighter timings...or lower speeds with less voltage and save on heat and power(not much but still some...)

You get the same ram for an e6600 or Q6600.....they use the same 533(266 in the bios) fsb
!