Thanks for the best wishes and the suggestion to check for BIOS updates. I'll do that.
I was hoping that someone might be running a CPU with a buss speed of 1333 on a motherboard with a system speed of 1066 and would be able to tell me that it will work fine or not.
I don't know enough about overclocking to understand whether the 1066 buss speed of the motherboard is something that is usually and easily changed or not. Nor do I understand whether there are stability or other problems with doing this that would justify getting a new CPU or motherboard instead.
So, please, if anyone has some information about this, I need your help in order to make up my mind whether to try this or go through the process of returning the CPU for another one, which in this case means waiting another week or so.
as far as i have heard that due to the chipset limitation, there will be a luck factor in this. i mean that some motherboards, i.e D975XBX2, will work while others will not. i know this sounds weird and this was the only reason y intel first brought an updated bios on their website and then removed it after a week, i think. one thing u can do is to google about the version that supported 1333fsb cpus and then try to download that bios from somewhere else. hope i helped.
I read through the BIOS information on the Intel.com site and several of the updates say they add 'Updated Processor Support' but they don't say anything more than that. No info on what processors or what kind of update to them.
Information from newegg.com site seems to indicate that this CPU/mb combo might be ok. The have one of their 'bundles' that includes a 1333hz CPU with a 1066hz motherboard. It's a different mb, though. Also, in one of the reviews on newegg.com for either the mb or the CPU, I can't remember which right now, one of the users says he's doing great with this combination.
So, I'm holding out hope that this combo would work but I don't want to get it assembled and find out it won't.
That's why I was hoping that someone would have already tried it and would know one way or the other.
The front side bus is linked with the cpu clock... To get the 2.66 ghz of the E6750, it works like 8(CPU Multiplier) * 1333 (FSB) / 4 (Cycles) = 2.66.
If the north bridge bus speed does not support 333 and only 266 (1066/4) it will not work. Think of it as logarithmic bases? (That analogy makes sense to me)
If you are in the market for a new processor at $200, the E6420 is a good choice and will OC fine. It also has a multiplier of 8, while the E6600 has a multiplier of 9. Hope this makes things clearer...
In terms of OCing, all these processors have locked multipliers, so you have to raise the FSB speed... but to start, they have to both be able to operate at the same base.
Edit - note that it is the the north-bridge on the mobo that determines whether it can support it... Certain mobos which initially say they only support 1066 may in fact be able to support 1333 with a bios update. It all just depends on whether or not the north bridge will accept it. I also found this, last updated August 27, http://support.intel.com/support/motherboards/desktop/d...
It does not list the E6750 as a supported processor.
Well, I guess I need to go get a different CPU that runs at 1066hz, then. Intel has responded to me about this issue as follows:
"Regarding your technical question, we regret to inform you that the Intel(R) Desktop Board D975XBX2 was designed to support processor front side bus speeds of up to 1066Mhz, therefore no support is provided for the new generation of Intel(R) processors with 1333Mhz FSB, not even with the latest BIOS version. "
I just wish things were more 'black and white'. They say it's not 'supported'. They didn't say 'it won't work'.
There ultimately is no real benefit that can be seen from 1066 to 1333, the performance difference is marginal. The main thing is to get a good OC out of your processor and memory. As I mentioned earlier, the E6420 is a good choice for you since it also has an 8 multiplier... If you have DDR2-6400 RAM, you can get the E6420 up to 3.2 ghz easily... You should have no heat issues with that processor.
There's a chance that your main board doesn't support the 1333MHz FSB CPU ID so it won't even complete POST saying that you have used an incompatible CPU. Like, when you put a 1066MHz FSB on an older 945 generation chipset main board which does not have the new voltage regulator. Beside as the OP said, take the safe road.