[nicholas.jones]

Hey all,

I am looking into getting a CFD desktop for work, and I am trying to get an estimate on prices/performance.

Looking around these forums, the i7-5820K is very popular. However, being a newer socket/DDR4, the price for motherboards/ram is significantly higher. Im looking at the cost savings by going with the i7-4790K, and I am wondering how the performance will compare.

I plan on running OpenFOAM over SSH, so the intel graphics with the 4790 helps to save a bit on graphics card (post processing can be done on my modest gaming machine at home). Looking at simulating thermal profiles of two phase systems, approx 50 million cells. It looks like I will be the only one using the computer, so simulations can be left running for a while.

In all, I estimate the i7-5820K to cost approx. $1600 CAD with tax and shipping. i7-4790K would be around $1100 CAD.

Is the i7-5820K worth the extra $$$?

[flotus1]

Yes.
Apart from the better performance in CFD applications (almost twice the cache, twice the memory bandwidth, 50% more cores) there is another important aspect you have to keep in mind.
With up to 50 million cells, you might find that the maximum of 32GB of RAM supported on the 1150 platform is not enough depending on the models you use. So make sure you get a 2011-3 motherboard with 8 DIMM slots. You can start out with 4 DIMMs of 8GB capacity and upgrade to 64GB later if you find that 32GB is not enough. And as always, make sure to get the fastest RAM you can afford.

[nicholas.jones]

Would you say the i7-5930K would be a significant improvement on the i7-5820K? Or is the only benefit a small increase in processor speed, with similar caches on both chips?

Thanks for your input!

[flotus1]

Don't care about the stock frequencies of these processors. They all come with an unlocked multiplier. The only additional feature of the I7-5930k is more PCIe-lanes. Unless you are planning to have more than one graphics card in your system the I7-5930k is a waste of money.