i7-4790K Vs. i7-6700K - Engineering CAD, FEA & CFD ?

[Amyrro]

Hello everyone

 

I have been searching about the latest in computer desktops, as I am planning to build my own rig for a coming project. My use of the machine is going to be basically focused on the analysis of fluid flow, and so, I will be using the machine to do a lot of Engineering CAD (Computer Aided Design), FEA (Finite Element Analysis), and above all CFD (Computational Fluid Dynamics), which is very CPU-intensive when involving gas flow.

 

I was about to order the parts of the build, and just before that I went across some news from different websites (including Toms Hardware) regarding a bug in the Skylake processors, which causes them to crash under heavy calculation tasks (involving prime numbers). 

http://www.tomshardware.com/news/skylake-prime-number-bug,30979.html

 

http://www.pcworld.com/article/3021023/hardware/how-to-test-your-pc-for-the-skylake-bug.html

 

I have had some experience with intensive FEA tasks before, when i7 processors (1st or 2nd Gen, I am not sure) took an hour or a little more to finish calculating the results. 

 

In this CFD task, I am expecting heavier calculations. I might even end up running simultaneous FEA & CFD tests. I thought about 4th Gen i7-4790K, as I did not find a lot of talk about such bugs in it, plus it gives comparable (or slightly better) single threaded performance, and added to that, I could find some discounted pre-built rigs, as system builders are trying to clear out their stock for the new Skylake builds. 

 

Before the bug news, I considered i7-4790K for its price and performance, but leaned more towards the Skylake for better "future-proofing" (as some like to describe it), and the expected better support for Skylake with future technologies on the long term. 

 

My question is, after the this news, is it worth to take the risk and rely on an i7-6700K in my case, especially that I cannot wait for the fix for long time (I can wait for a month max). Added to that the fact I do not quite trust BIOS fixes, as I did not have pleasant experience with Samsung and HP and their BIOS fixes for hardware issues.

 

Sorry for the long thread

 

Regards

 

[thekeemo]

the issue with skylake will be fixed with a bios update

[Neemil]

For the price of a Skylake system you could build yourself a Haswell-E system with a 5820K.

[stealth80]

I don't know too much of this software, but would a 5820K offer greater benefit? If so the platform can usually be had for around the same price as a Skylake platform 

[Andrew Storlie]

Yea as above me... 5820k all day long, and Intel is even coming out with a new line of x99 chips so youll have room to upgrade later on

[Edwardk326]

I have to agree with what others are saying i7 5820k x99 motherboard. It will really haul when you do cpu intensive tasks like 3d rendering, compiling, CAD, and fluid dynamics. Luke at luke from linus tech tips he built a desktop for cpu intensive tasks like boinc and folding

[Amyrro]

the issue with skylake will be fixed with a bios update

 

Thanks for your reply mate

 

The question is, when is the fix expected to come out ? How practical is it going to be, aside from the commercial take or corporations ?

As I mentioned earlier, I did not have a very pleasant experience with Samsung and HP fixes of hardware issues through BIOS fixes.

 

Is there going to be a better chance of a real fix with Intel ? 

 

Regards

 

[thekeemo]

Thanks for your reply mate

 

The question is, when is the fix expected to come out ? How practical is it going to be, aside from the commercial take or corporations ?

As I mentioned earlier, I did not have a very pleasant experience with Samsung and HP fixes of hardware issues through BIOS fixes.

 

Is there going to be a better chance of a real fix with Intel ? 

 

Regards

That is their real fix

MSI already has the fix

[Amyrro]

For the price of a Skylake system you could build yourself a Haswell-E system with a 5820K.

 

Thanks for your reply mate

 

You are right. However, the i7-4790K and i7-6700K are better than the Haswell-E in single-threaded performance, which I count on in CFD. Especially the clock speed, which is a major factor in this the single-threaded processing capability as you know.

 

Regarding the Skylake and the Haswell-E, do you ever think that going for the older Haswell i7-4790K is going to be worth it, due to is superior performance and lower price (about a 100$ cheaper than both, plus that I could  find some discounted pre-built rigs, which creates a larger price margin for the entire build).

 

Regards

[Amyrro]

I don't know too much of this software, but would a 5820K offer greater benefit? If so the platform can usually be had for around the same price as a Skylake platform 

 

Thanks for your reply mate

 

The Haswell-E may provide higher reliability, which is a attractive in serious work. However, most engineering analysis packages, and more particularly CFD software, are still based on the old school principles, and do not offer the chance to exploit multi-cores. The single-threaded performance of a processor is a key factor in this. As you know, the clock speed is a key in determining the single-threaded performance of a processor, aside from the fact that both i7-4790K & i7-6700K score higher than the Haswell-E CPUs in the single-threaded performance benchmarks. 

 

Regarding the Skylake and the Haswell-E, do you ever think that going for the older Haswell i7-4790K is going to be worth it, due to is superior performance and lower price (about a 100$ cheaper than both, plus that I could  find some discounted pre-built rigs, which creates a larger price margin for the entire build).

 

Regards

[Masada02]

Thanks for your reply mate

 

You are right. However, the i7-4790K and i7-6700K are better than the Haswell-E in single-threaded performance, which I count on in CFD. Especially the clock speed, which is a major factor in this the single-threaded processing capacibility as you know.

 

Regards

Are you sure CFD relies on single threaded performance? From my experience with modeling, simple CFD, and FEA the more cores you have the quicker calcs will run. Although with ANSYS you have to purchase access to more cores within the program. I can't remember if educational licenses are fully unlocked, but in the professional world access to more cores over 2 costs $2500 per core.

 

EDIT: Autodesk CFD recommends a dual Xeon system...

[stealth80]

Thanks for your reply mate

 

The Haswell-E may provide higher reliability, which is a attractive in serious work. However, most engineering analysis packages, and more particularly CFD software, are still based on the old school principles, and do not offer the chance to exploit multi-cores. The single-threaded performance of a processor is a key factor in this. As you know, the clock speed is a key in determining the single-threaded performance of a processor, aside from the fact that both i7-4790K & i7-6700K score higher than the Haswell-E CPUs in the single-threaded performance benchmarks. 

 

Regarding the Skylake and the Haswell-E, do you ever think that going for the older Haswell i7-4790K is going to be worth it, due to is superior performance and lower price (about a 100$ cheaper than both, plus that I could  find some discounted pre-built rigs, which creates a larger price margin for the entire build).

 

Regards

 

 

If that is true that it relies on single threaded then get the Skylake 6700K. Its a newer platform, will last longer, its faster per hz than haswell and is using DDR4 whilst also providing more PCI lanes 

[Amyrro]

I feel an actual Xeon would be better for this or a higher set of Opterons.  However, the 5820k can handle more work loads with 6 cores and what? 12-threads?  It probably has a larger overall cache too in support of all of that.

 

Thanks for your reply mate

 

The XEONs, and to less extent Haswell-E, may provide higher reliability, which is a attractive in serious work. However, most engineering analysis packages, and more particularly CFD software, are still based on the old school principles, and do not offer the chance to exploit multi-cores. The single-threaded performance of a processor is a key factor in this. As you know, the clock speed is a key in determining the single-threaded performance of a processor, aside from the fact that both i7-4790K & i7-6700K score higher than the Haswell-E CPUs in the single-threaded performance benchmarks. I count on the single threaded performance in CFD more, especially the clock speed, which is a major factor in this the single-threaded processing capability as you know. Thus, the extra cores and threads may not make a significant addition to the performance, while the cache might compensate little of the performance gap. 

 

Regarding the Skylake and the Haswell-E, do you ever think that going for the older Haswell i7-4790K is going to be worth it, due to is superior performance and lower price (about a 100$ cheaper than both, plus that I could  find some discounted pre-built rigs, which creates a larger price margin for the entire build).

 

 

Regards

[Amyrro]

Are you sure CFD relies on single threaded performance? From my experience with modeling, simple CFD, and FEA the more cores you have the quicker calcs will run. Although with ANSYS you have to purchase access to more cores within the program. I can't remember if educational licenses are fully unlocked, but in the professional world access to more cores over 2 costs $2500 per core.

 

EDIT: Autodesk CFD recommends a dual Xeon system...

 

You got the point. As far as I know, the license we have at our university allows access to a single-core only.

[Amyrro]

If it has better performance than get that, especially if it is going to be 100 bucks cheaper.  However, the DDR4 may or may not help you, so that might be something you want to research.

 

Other than the DDR4, my the main point in the Haswell is that it is an older technology, and I am not sure if it is going to be supported long enough. Any thoughts ?

DDR4 ram might add some marginal benefit, but it may not be significant. 

 

Regards

[Amyrro]

That is their real fix

MSI already has the fix

 

Interesting !

 

I checked their website and I did not find a clear mentioning of that. I may contact them

 

Thanks

[Prysin]

CAD and similar workloads are going to run better with GPU acceleration.

 

Both AMD and Nvidia supports this, albeit Nvidia has the edge with CUDA mostly through wider adoption rate then AMDs OpenCL solution.

[TheCaptain53]

I may be ignorant in this matter, but my impression would be that gas flow calculations would be greatly benefited by the superior parallel compute performance of a GPU?

I would go for the 5820k as everyone else suggested and just overclock it for the better single threaded performance. Clocking it to 4-4.4 GHz is a fairly easy task, will have the same single core performance as a 4790k, but has quad-channel DDR4 memory. This could help with the compute.

Just my two cents. I don't know much about these kinds of workflows, so ignore me if I'm wrong.

[arnavvr]

Neither, the 5820K and an X99-A will perform much better.