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Lowering CPU multiplier

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April 6, 2010 3:03:45 AM

I'm trying to overclock my computer, I've gotten the processor from 2.3GHz to 2.8GHz, which I'm pretty content with. At this point, I am unable to increase my FSB any more or else it will fail to boot. However, at this bus speed my RAM is not running at its full 1066MHz but rather at about 975MHz. I would *like* my ram to be running at its full speed (since I just bought this DDR2-1066 to replace my DDR2-800 ram), but in order to do that I would have to increase my FSB by about 22MHz. I'm wondering if anyone can tell me if I might have luck increasing my FSB to get my ram running at its full speed whilst lowering my cpu multiplier so that it's clock speed remains at around 2.8GHz, thus hopefully enabling my system to boot. On the surface, this makes sense because right now my FSB is only running at 244MHz (with a 11.5x cpu multiplier) which doesn't seem like it is unreasonably high. Of course this wouldn't be a problem if I had more options for the FSB:RAM ratio, but after 1:2 the next choice is 1:2.66 which would shoot my ram speed through the roof. This sort of boils down to a question of what I am limited by, my max cpu speed or my max FSB speed I should also note that my processor is NOT a black edition (unfortunately), so I won't be able to increase the cpu multiplier past 11.5x. Thanks a ton in advance for any advice or input you can offer me! :) 

My system specs:

Microsoft 7 Ultimate 64-bit
AMD Phenom 9650 @2.8GHz
30 GB OCZ Vertex SSD, 160GB and 320GB WD HHD's, 16MB 7200rpm
4GB OCZ PC-8500 Ram
MSI K9N2 SLi Platinum mobo
eVGA 9600GT 512 MB video card
550 Watt Antec psu
April 7, 2010 10:36:24 PM

okay, you need to increase your core voltage and increase your fsb. dude you have a lot of stuff in there and i don't have the patience to read it:p  you need to just bullet it out or something.
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April 8, 2010 1:52:35 PM

975 to 1066 isn't going to make much of a difference in the real world, it's just something you have to deal with when overclocking. Personally when I over clock I will significantly underclock the ram then see how far I can push the cpu, then drop the cpu way down and see what the ram is capable of. Once I have the two numbers I go through all the different combination of multipliers to see what I can actually use. Once you overclock your ram you may find that using the 1:2.66 multiplier is a viable option.
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a b K Overclocking
April 8, 2010 1:57:29 PM

It's likely your hypertransport bus that is giving you problems. Lower the multiplier on it, and then you should be able to keep going up with the FSB speed.
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April 8, 2010 5:48:25 PM

Ok, here it is in bullet point form, for those tl;dr'ers out there (I admit I'm typically among them :p  )

>Cpu (not unlocked) is currently oc'd from 2.3 to 2.8GHz, want to go higher (temps max at 55C during Prime95)

>1066MHz ram running at 975, not that big a deal I suppose

>FSB won't go any higher (currently 244) and still boot (HT link multi is at 7x, freq is ~1700MHz)

>Voltages: Cpu at 1.325, ram at 2.1, NB at 1.35, HT link at 1.35

What I'm thinking might be the problem is that my NB frequency is getting too high, it has a locked multiplier at 9x giving a frequency of 2194MHz. What might be happening is that once it exceeds 2200MHz the system is no longer stable, but this is just a guess. Would increasing the NB voltage even more possibly give me more room for a higher NB clock?
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April 9, 2010 8:06:49 AM

na, your NB can go up, mine goes to 2500 sometimes, what you should be worried about is your core volts. because even though you can boot, you might not be stable at 100% load and chances are that your computer will lock up and shut down when you do something intense, you need to get prime95 and run the torture test and make sure that your computer can take it for at least 6 hours with no errors, if your computer shuts off, you're probably making it do too much, tell us how that goes.
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a b K Overclocking
April 10, 2010 7:36:59 AM

The reason the OP is hitting a wall is because the average 9650 tops out at 2.8/2.9Ghz. Sorry to give you the bad news but the agenas are not good overclockers. I have a 7750 which is actually a crippled agena and it wont do more than 3.1Ghz stable.

975Mhz is basically the same as 1066Mhz, not much of a difference. Better to have a stable 975Mhz as opposed to 1066Mhz unstable.

I also have the OCZ 1066Mhz and my G.Skill (6400) @ 960Mhz with lower timings runs circles around the OCZ.

The AMD mem controller has a hard time with 1066 sticks, especially at 2.1v and above =)





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April 10, 2010 6:41:42 PM

Damn, I guess there's not much more I can do then =/

And to answer dickcruz, I ran prime95 for about 6 and a half hours last night and it was fine.

I suppose next time I buy a new processor I should do a bit more research on how well they will overclock. Not that I'm necessarily complaining, it's a fine cpu, I just had some pipe dream of seeing 3GHz out of it.
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