Gents i have been trying to find on the net how many Haswell cores actually boost to the elevated boost clocks. Is it just one or all four that will boost on demand? Still rocking an old i7 920 but may consider an update to Haswell. Thanks in advance!
I think the limiting factor is heat so the better cooler the more cores and higher the boost will be. Any AIO water cooler like the H80 should give you max boost. See my sig I just set Asus bios to auto OC and have a extremely stable 3.7 GHz OC, F@H stable
So assuming the cooling is good enough would say a non 'K' haswell processor boost to the maximum clock speed across all cores. As an example the new refreshed 4590s haswell chip quotes 3.7ghz. If i had one in a z97 board would i see this level of boost when playing BF4 etc.
It will boost, but all four cores do not boost to the maximum, one and two cores loaded boost the highest and if all four are in use, it drops by one multiplier (usually). You can set it to run at stock speeds with an offset to "turbo" to an overclocked speed but in all honesty, just set it to run at those speeds all the time. It saves a lot of hassle, and doesn't really chew that much extra in terms of electricity.
I would recommend you finding the table like this for CPU you have choosen : Those are the defaults (coluimns 1 core-4 cores are the turbo clocks). In case of a Z series motherboard and a non-K CPU you can sometimes modify all four turbo clocks to the same value as the 1-core turbo clock, but this is not guaranteed. In case of a K-series CPU, you can of course change the basic multiplier to changer the clock rate and also all four turbo multipliers to any values up to 57 i think (but good luck booting at anything higher than 45-51 depending on how lucky/unlucky you are). If you can wait a day, i will get my ASRock Z97 Extreme6 board and the i5-4460 CPU, so i will be able to try if my combo will push all 4 cores to turbo to 3.4GHz or not.
Thanks folks i may just end up buying the 'k' version of the 4690 when its released to guarantee a good clock speed.
Result of Z97 Extreme6 + i5-4460 - all cores can run with 3.4GHz Turbo (the maximum Turbo multiplier for this CPU). Going by the logic of the table above, the pretty much equivalent CPU would have been i5-4430 in Haswell era - and as you can see, it had 3.2GHz on 1 & 2 core load, 3.1GHz on 3 core load and 3.0GHz on 4 core load. I have 3.4GHz on all 4 options, so with a board which supports it, it can be owerwritten by the BIOS to have all four Turbo clocks identical to the maximum Turbo clock allowed for that CPU. Of course setting higher Turbo clock alone is not enough, because you can still hit TDP or thermal limitations.
No such thing as a guarentee with cpus, You get the poor which run stock and a slight overclock. The average which most are and what most people aquire unless your willing to sell and buy cpus to get a good one. If you do get a K series you can overclock it and set it to offset so its not burning away at 4.5ghz or whatever speed you set it at perm. Even ignoring the increased electric cost, The extra requirements on your cooling system is another reason its best avoided. Core management is done by load. If you have a hyper threaded system and load all 8 threads say to 100% the cpu will automatically notch it down a level on most motherboards there is a few that do not do this. That does not change the Thermal or TDP limits that the chip has though where by it will automatically declock itself if it exceeds those limits.
Cooling limits. Pfft. He's not overclocking on a stock cooler. My idle temperatures rose by a couple of degrees, if that, when in a 4.5 or 4.7GHz configuration. That's without EIST/C1E/C6/C7 states enabled.
Well it seems that the haswell refresh chips boost very well. I have just put together a little mini itx build using the asus z97 mobo, 4590 cpu and i can confirm that this nice little chip boosts to 3.8gig across all four cores without breaking a sweat. I am running the standard cooler and the max temp i have seen is 57 degrees when playing bf4. I think the cooler is sucking in warm air from my gpu as when stressing the cpu only it runs around 48 degrees. Glad i didnt hold out for the 'k' series of chips.
