Hi guys ,maybe this s not the right forum but i don't want te register to a oc forum for just one question so hope to get an answer here.I overclock my i7 950 to 4312 mhz using multiplier 21 and bclk 205 , is this ok or should i use multiplier 23 and bclk 187Best regards,Thanks in advance Gérard

Multiplyer 23 and bclk 187.

Multiplyer 23 and bclk 187.

Why? Not a disagreement just what made you make that call?

If stability , cooling is good and all other things are equal (like Memory timing etc) then you'll get better performance out of 21/205.

If stability , cooling is good and all other things are equal (like Memory timing etc) then you'll get better performance out of 21/205.

Also not a disagreement, just a question.Why would 21/205 give you better performance than 23/187?I have always heard that the lower the BCLK the better because a lower BCLK requires less vcore.Also a lower BCLK will generate less heat. When you add the lower vcore into that you get even less heat.This of course assumes that the lower BCLK is just as stable as the higher BCLK.

+1 Idahosurge. Exactly what I was planning on saying.

Because you overclock higher the uncore and the QPI link with a higher BCLK. The uncore controls the IMC and L3 cache and the higher QPI link provides increased maximum bandwidth between the CPU and the PCIe devices (mainly graphics)In my tests however, it had no impact in FSX. I tested 4.2GHz at 21x200 and 19x221, and also 3.8GHz at 21x181 vs 17x224. No difference at all in my system

Also not a disagreement, just a question.Why would 21/205 give you better performance than 23/187?I have always heard that the lower the BCLK the better because a lower BCLK requires less vcore.Also a lower BCLK will generate less heat. When you add the lower vcore into that you get even less heat.This of course assumes that the lower BCLK is just as stable as the higher BCLK.

Hi,I'm not sure how I could have re-worded it for you. I mentioned as long as cooling was not a problem for you as 21/205 can be run perfectly fine on many boards with decent cooling (we are talking about overclocking and performance right?) otherwise I would suggest running at 23/300 is even better etc.Or were you asking which is cooler? The way you seem to be reasoning maybe you should run at a slite underclock and undervolt for better performance because it sure runs cooler that way...??? Anyway See the post from Dazz

No difference at all in my system

Hi Dazz,Its not like you will see a lot with the frame counter anyhow (just look at reviews of faster memory and effects of more ram etc to get an idea), but if you dont see >ANY difference with those settings then your bottleneck is probably somewhere other than just CPU & memory-sub-system, running some conflicting settings somewhere OR your not sure what to expect and are looking for too much of an FPS improvement perhaps?

Hi Dazz,Its not like you will see a lot with the frame counter anyhow (just look at reviews of faster memory and effects of more ram etc to get an idea), but if you dont see >ANY difference with those settings then your bottleneck is probably somewhere other than just CPU & memory-sub-system, running some conflicting settings somewhere OR your not sure what to expect and are looking for too much of an FPS improvement perhaps?

I know, I know mate. I'm not expecting a day and night difference, but with a 24% uncore/QPI boost there's nothing at all that could help me tell one from the other. Not the fraps bench, neither perceived smoothness. I dunno, maybe I'm missing something obvious, it wouldn't be the first time, but there was the expected ~5% boost going from 3.8GHz to 4.0 and then to 4.2GHz, so I'm pretty sure the bottleneck is there in the CPU as expected at 8xSQ AA. Anyway, that's something that anyone can test so I would say to the OP, do your homework. Test those different configs. I guess It's not the higher BCLCK what asks for mor volts, it's the fact that you're pushing your IMC (so probably you will need to raise you Vimc / Vtt instead) but you can get the same outcome (or close) with a lower BCLCK and higher uncore & QPI multies in x58 boards where those multies are not locked like they are in my p55.Pick the config that let's you max out your memory, uncore and qpi link. Use your muiltipliers. Test them and pick the one you like best. There's the obvious limitation of an ultra high BCLCK where you might need to bump your Vpll too, but 205 is not even close to the limit as freebird said, so you'll be fine either way

Hi guys , I tried to use the mp 23 with bclck 187 but can't get it stable , with the mp 21 ,bclck 207 it is rock stable vcore 1.36250 , cpu/pll 1.60325 ,qpidram 1,30 .temp are 69 celsius on watercooling, think that there is even more possible .Thanks in advance , Best regards,Gérard

Maybe it's not stable at 187 BCLK because of the uncore-memory ratio limitation: the uncore has to run at least at twice the speed ram does in x58. What multies are you using for ram and uncore? I guess that's not the problem because for what I know if you don't meet that condition, it won't even boot, but stillThose temps are under full load? it looks like a great OC. Good job

Hi guys , I tried to use the mp 23 with bclck 187 but can't get it stable , with the mp 21 ,bclck 207 it is rock stable vcore 1.36250 , cpu/pll 1.60325 ,qpidram 1,30 .temp are 69 celsius on watercooling, think that there is even more possible .Thanks in advance , Best regards,Gérard

Hi,The way you seem to be reasoning maybe you should run at a slite underclock and undervolt for better performance because it sure runs cooler that way...???

No I am not saying that, I am saying that all other things being the same a lower BCLK runs cooler and requires less vcore and that equals less stress on everything.Or look at it this way, if you want to run at 4.2GHz then you should go for the lowest BCLK that is stable. Of course everything is a trade off and as Dazz stated you have to take into account your QPI freq and your Dram freq so I go for the lowest BCLK that I can get while still getting acceptable QPI and Dram freq's.This is handy for looking at all the different combinations available.http://icrontic.com/files/apps/nehalem-calc

Hi,temps under full load with intel burntest maximum 69C ,dram 1643 uncore auto ,when i try 4500mhz temps go up to 76Celsius but can't get it stable so far .Best regards, Gérard