Intel i7 3820 overclocking question

Manziak

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Dec 10, 2011
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After days and days of research, i am going to wait till Q1 of 2012. I want the 3820 because its affordable at 290usd and uses x79 chipset. Ho wever, i want to overclock this cpu. Since its not a K or X sandy bridge cpu, it doesmt have an unlocled multiplier. I read on anandtech.com that this cpu has a multiplier of 43x max. Those this mean that i can overclock this processor with all cores to a max of 43x100mhz [base clock]? Also i heard that you can increase the baseclock to125 mhz. Those this increase all cores base clock to 125mhz?

Can someone explain to me how overclocking on this chip works?

Ps. When is the new nvidia kepler gpus coming out¿
 

Manziak

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Yeah but i kinda dont understand what anandtech means when there is a limit of 43 bins on a cpu amd at the same time they say that the processor doesnt have any multipliers
 

cbrunnem

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yes your can set the baseclock to 125 and yes without changing the baseclock your max speed would be 4.3 but the catch is that 4.3 is only obtainable with 1 core active and if you havent gone over the heat thresh hold. the maximum multiplier with all cores active seems to be 40 or 4.0 ghz. if you change to baseclock the max sustainable would be 5.0 ghz i suppose.

read this if you already havent
http://www.anandtech.com/show/5276/intel-core-i7-3820-review-285-quadcore-sandy-bridge-e
 

Haserath

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The chip is partially unlocked, so you can do some overclocking on the cpu multiplier.

The overclocking looks likely to be you up the base clock to 125mhz(boosting it 25%), then you can change the multiplier to 4 bins higher than the stock multiplier if your chip can reach that speed.

5ghz appears to be the maximum for this chip@the 125mhz boot strap(I don't know if there will be higher ones that work), but even most 1155 chips don't reach that and even this chip might not reach that.

It does look like memory speed is affected by the base clock still, so you might have to watch that while overclocking. There might also be other speeds affected by that base clock change, and they could cause instability if they are raised. It looks like Anand just changed the base clock and had no trouble.
 

cbrunnem

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+1 but it looks like the motherboard adjusts for the baseclock raise so there should be no instabilities there.
 

cbrunnem

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for pure gaming id prolly get the 3770k just to have the integrated graphics just in case. the performance hit from x8 x8 is to small for me to buy a 3820 and justify the cost and not having a backup gpu.
 

Haserath

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3820 if you need the extra pci-e connectivity.

3700k for the max processor performance and good enough connectivity(Pci-e 3.0 at x4 should handle gaming cards today). Overclocking has always given the enthusiast more with each node shrink, so this one shouldn't be that different.

For most enthusiasts, the 3700k would be a better deal. As Anand put it, the 3820 is a "niche within a niche". Those not willing to spend too much, but want the connectivity of X79, will buy the 3820.
 

a4mula

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lga2011

The +4 applies to BCLK, not multipliers. Its multiplier is maxed at 43 regardless.

While this is a partially locked cpu that doesn't mean nearly as much as it did for 1155 because of 2011 ability to adjust the BCLK from the base 100mhz to 125 (+4 129), 166 (170), or 250mhz (254).

What this means ultimately is while this chip isn't going to be Sandy Breeze to overclock, it's also not stuck in the same boat as say the i5-2400 where you can only squeeze another 5%.

In the AnandTech review he was running a BCLK of 125 and a 38 multiplier for his final speed of 4.75ghz.

This was also done on an intel board (notoriously not great for oc), with an intel prefab watercooler.

With proper cooling and the right board there's no reason this chip couldn't break 5ghz.

The point though is that while this is only a "partially" unlocked chip that means little because of LGA2011 extra BCLK straps.
 

cbrunnem

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the plus 4 is definitely NOT on the base clock. it is the number of bins you can overclock past the max turbo for the amount of cores being used. so if 1 core is being used max turbo is 3.9 or multi of 39 giving you a max multi of 43.
 

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