The Definite Answer On QPI Speeds??

lettuce · 27 May 2010 at 21:41

I have heard 2 conflicting suggestions when refering to the QPI speed when overclocking on the Intel i3 & i5 chips, which are:

The QPI should be as close to the cpu speed as possible, so if:

cpu was oc to 4ghz, the the QPI should be set to 8ghz in the bios which shows up as 4ghz in cpu-z

ALSO

The QPI should be set to double your memory speed, so if:

memory speed is 1600mhz, then the QPI should be set to 6.4ghz in bios which shows up as 3.2ghz in CPU-Z

So which is the correct statment???

OpenToSuggestions · 27 May 2010 at 21:45

I thought that the QPI does nothing but set it to the lower multi when overclocking as it can cause instability otherwise.

For the i3 I did hear something about keep it in line with the cpu or something, but when you overclock like crazy (as in 4.4ghz ish) the QPI gets left behind and performance suffers a tiny bit.

I have no source to give though so I may be wrong.

lettuce · 27 May 2010 at 22:35

yeah this is what im finding, no definite answer, im not sure whats best for stablilty

DIABLO · 27 May 2010 at 23:11

It's the Uncore that has to be twice the speed of the RAM you can set the QPI to what ever muliplier you want but people generally keep it on the lowest one to keep the QPI speed as low as possible so they can get the BCLK higher. i3 & and i5 don't have a QPI link they use something called DMI instead.

lettuce · 27 May 2010 at 23:42

DIABLO said:
It's the Uncore that has to be twice the speed of the RAM you can set the QPI to what ever muliplier you want but people generally keep it on the lowest one to keep the QPI speed as low as possible so they can get the BCLK higher. i3 & and i5 don't have a QPI link they use something called DMI instead.

Well i3 and i5 dont have uncore value in the bios do they? On my i3 ive have the bclk set to 173 and cpu at x22 which gives me the 4Ghz OC i want, so in this instance would ideally would i want he qpi to be set at? As at the moment i have it the same speed at my cpu, 4ghz (8ghz) in the bios which i think is x44 muliplier for the qpi. Would i want to set the qpi as low as possible, will this not effect performance if say i only has the qpi at 2ghz??

lettuce · 28 May 2010 at 11:07

So if your happy with an OC you have, whats the ideal setting for the QPI?? The same or close as the cpu OC or, as low as you want?? In setting the QPI clocker lower does this require less voltage on the vcore or more?? Or is there a happy medium to set the QPI at??