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Elegy
07-10-07, 09:52 AM
There will be a plethora of cheap Core 2s coming out on July 22nd with a bus of 1333MHz, but how exactly will the speed of such processors be affected if they were put into a motherboard which only supports 1066MHz?

Will their speed effectively be cut by (1066/1333), which is about 20%, or will they still function at the same speed but with a lower bus? Eg, an E6750 works at 2.66GHz. If placed in a 1066MHz motherboard, will it's speed be reduced to just 2.13GHz or will it still run at 2.66GHz with a reduced bus? The effective speed of intel chips is multiplier*bus I believe and the E6750 has a locked multiplier, so wouldn't that mean it would run slower at a slower bus?

Can bios updates allow compatibility for 1333MHz CPUs? Can the new Core 2s even fit into 1066MHz slots in the first place?

nekrosoft13
07-12-07, 01:00 PM
not sure how speed would be affected.

but i can answer the last two options, bios update might be possible in some cases, but not likelly, you should be able to OC the motherboard to 1333mhz bus. CPUs will fit, its the same socket no difference in pin layout.

|JuiceZ|
07-12-07, 02:32 PM
More than likely the multiplier would stay the same and the cpu would just run at a slower 1066Mhz FSB unless your board mfgr came out with a bios update to support 1333mhz.

lduguay
07-12-07, 02:39 PM
There will be a plethora of cheap Core 2s coming out on July 22nd with a bus of 1333MHz, but how exactly will the speed of such processors be affected if they were put into a motherboard which only supports 1066MHz?

Will their speed effectively be cut by (1066/1333), which is about 20%, or will they still function at the same speed but with a lower bus? Eg, an E6750 works at 2.66GHz. If placed in a 1066MHz motherboard, will it's speed be reduced to just 2.13GHz or will it still run at 2.66GHz with a reduced bus? The effective speed of intel chips is multiplier*bus I believe and the E6750 has a locked multiplier, so wouldn't that mean it would run slower at a slower bus?

Can bios updates allow compatibility for 1333MHz CPUs? Can the new Core 2s even fit into 1066MHz slots in the first place?
I would assume that the E6750 Multiplier will be set to 8 (6-8), i think the E6850 would OC better on a 1066 Mobo.

Despotes
07-12-07, 02:42 PM
eVGA has a bios out for the 680i that supports 1333 cpu's.

Both are the same socket size and pin number

Burner_Tbird2
07-12-07, 02:59 PM
X-Bit Labs Test of New 1333Mhz Core 2 (http://www.xbitlabs.com/articles/cpu/display/core2duo-e6850.html)

Elegy
07-12-07, 04:02 PM
I'm not interested in overclocking potential or comparing processors of similar clock speeds but different FSBs (as these have different multipliers), I was just wondering how the speed of an E6x50 processor would be affected if it was placed in a 1066MHz FSB motherboard and I know the answer now; Since the multipliers are locked, reducing the FSB will inevitably reduce the clock speed of the CPU. The E6750 has an 8x multiplier for example so reducing the FSB from 1333 to 1066 will reduce it's clock speed from 2.66GHz to only 2.13GHz.

Thank you for the replies though.

jcniest5
07-12-07, 04:11 PM
I'm not interested in overclocking potential or comparing processors of similar clock speeds but different FSBs (as these have different multipliers), I was just wondering how the speed of an E6x50 processor would be affected if it was placed in a 1066MHz FSB motherboard and I know the answer now; Since the multipliers are locked, reducing the FSB will inevitably reduce the clock speed of the CPU. The E6750 has an 8x multiplier for example so reducing the FSB from 1333 to 1066 will reduce it's clock speed from 2.66GHz to only 2.13GHz.

Thank you for the replies though.

In many cases, your system may not even boot if it doesn't support 1333FSB. It's just the same as putting a Prescott CPU into a board that doesn't support it. At worst, if it does boot or work, you will not be able to use the full potential speed or feature of the CPU. Depending on which board you have, a new BIOS may fix it if it's made with a future-proof upgradibility. Otherwise, you will just have to buy a new board that will work with such CPUs.

$n][pErMan
07-12-07, 04:27 PM
I'm not interested in overclocking potential or comparing processors of similar clock speeds but different FSBs (as these have different multipliers), I was just wondering how the speed of an E6x50 processor would be affected if it was placed in a 1066MHz FSB motherboard and I know the answer now; Since the multipliers are locked, reducing the FSB will inevitably reduce the clock speed of the CPU. The E6750 has an 8x multiplier for example so reducing the FSB from 1333 to 1066 will reduce it's clock speed from 2.66GHz to only 2.13GHz.

Thank you for the replies though.
Sence when did they lock the multiplier on the C2D's? Is this something new with the 1333FSB chips?

CaptNKILL
07-12-07, 05:10 PM
[pErMan']Sence when did they lock the multiplier on the C2D's? Is this something new with the 1333FSB chips?
They are all locked upwards as far as I know.

Madpistol
07-12-07, 05:47 PM
They are all locked upwards as far as I know.

Correct. Only the Extreme series of processors have an unlocked multi up.

$n][pErMan
07-13-07, 06:47 PM
They are all locked upwards as far as I know.
Ahh upward... ok. Cause I know I can change mine down so I was not sure what you were talking about for a second :p