[marco.pasotti]

Hi everybody I have to assembly a pc for 3d modeling, FEM and CFD calculations.
which one is preferable?
- 5820k little older, lower clock, higher bandwidth and 6 cores
- 6700k newer architecture, higher clock, lower bandwidth, 4 cores
Thank everybody in advance

[HyperNova]

hi, both of them featuring great performance , but i suggest for problems with huge number of cells go for i7-5820k, higher bandwidth plays an important roll in quicker solving big problems. by overclocking it up to 4.2, i7-5820k can have the same clock. after intel decided to raise i7-6700 price now they cost the same and even 5820 is a bit cheaper.

[evcelica]

I agree with HyperNova. Memory bandwidth is much more important than CPU speed. i7-5820K will be much better for a workstation, and for FEA / CFD which are highly memory bandwidth sensitive.

[HyperNova]

Originally Posted by evcelica

I agree with HyperNova. Memory bandwidth is much more important than CPU speed. i7-5820K will be much better for a workstation, and for FEA / CFD which are highly memory bandwidth sensitive.

Thanks "evcelica",, i always pursue your informative comments.

[sharonyue]

Originally Posted by HyperNova

hi, both of them featuring great performance , but i suggest for problems with huge number of cells go for i7-5820k, higher bandwidth plays an important roll in quicker solving big problems. by overclocking it up to 4.2, i7-5820k can have the same clock. after intel decided to raise i7-6700 price now they cost the same and even 5820 is a bit cheaper.

I have a i7-5820k with a powerful cooler. but I dare not to overclock. Have u ever tried to overclock it and run it for a long period? e.g. 100 hours?

[HyperNova]

Originally Posted by sharonyue

I have a i7-5820k with a powerful cooler. but I dare not to overclock. Have u ever tried to overclock it and run it for a long period? e.g. 100 hours?

In my opinion a powerful cooler is a 240mm cooler having at least 2 fans (4 is better). If u have such a fan try it. but do it gradually. i think 4.0Mhz or 4.2Mhz is ok although i have seen more than that (4.3Mhz). The performance boosts between 20 to 35 percents. again be careful, power is also important, a 750 watt or more is better for overclocking purposes.

[sharonyue]

Originally Posted by HyperNova

In my opinion a powerful cooler is a 240mm cooler having at least 2 fans (4 is better). If u have such a fan try it. but do it gradually. i think 4.0Mhz or 4.2Mhz is ok although i have seen more than that (4.3Mhz). The performance boosts between 20 to 35 percents. again be careful, power is also important, a 750 watt or more is better for overclocking purposes.

I dont have that cooler, but with the cooler now I have, when the 12 threads are fully occupied. Temp is around 47 degree.

So does that mean, if I can keep my CPU's Temp below 70 or 80 degree, I can overclock it?

Thank you.

[HyperNova]

Originally Posted by sharonyue

I dont have that cooler, but with the cooler now I have, when the 12 threads are fully occupied. Temp is around 47 degree.

So does that mean, if I can keep my CPU's Temp below 70 or 80 degree, I can overclock it?

Thank you.

yes u can, but again i say do it gradually (100Mhz) and test system stability.

[sharonyue]

Originally Posted by HyperNova

yes u can, but again i say do it gradually (100Mhz) and test system stability.

Gotya! I will try it. Indeed we need to overclock xxx-k family CPUs.

[sharonyue]

Ha! I oc my 5820k to 4Ghz. Faster!! Check it out here: http://www.cfd-online.com/Forums/har...-clocking.html