6700K vs 5820K, Without overclocks?

[aaronmontero]

Hello there!

 

I'm looking to upgrade my freelancing computer from an ancient i5-760 (quad, no HT, 2.8Ghz), and I'm having trouble deciding between these two chips:

 

6700K, 32GB, 4 cores at 4.0Ghz, for $611 USD.

5820K, 32GB, 6 cores at 3.3Ghz, for $733 USD.

 

I'm looking to do the following:

- Modeling with 3DSMax/Zbrush

- Texture work with Photoshop/Quixel

- Rendering interiors and products with VRay

- Use VRay RT for lighting testing and look dev.

- Work with realtime engines (and some VR) in Unity and Unreal.

- Some video editing and 3D compositing.

- A bit of animation rendering.

- Bit of gaming, but I know either is just as good for this.

 

I've read here and in other places that both chips are very comparable, in spite of the different core count, but does this hold true when we consider these other purposes? The Corona benchmarks still place the 5820K above the 6700K, and chances are the French VRay benchmark out there that suggests otherwise isn't taking into account that Light Cache is singlethreaded, and that tip the result in the 6700K's favor.

 

As it is right now I've basically been avoiding CPU rendering as my GTX970 can do it much faster, but I've also run into its limitations quickly when it comes to interiors.

 

Baking textures for realtime objects with my current cpu also poses some problems, some simple models can take 22 minutes for one of several passes in xNormal, making iterations an absolute pain.

 

In the case of large VRay renderings, I don't have access to a render farm, so I'm thinking of using a cloud rendering solution when the need arrives, regardless of the chip. However, I'd like to be able to rely on my system, even if it involves waiting for a while. I can't afford a dual Xeon machine either.

 

For a variety of reasons, I can't risk my equipment by overclocking. RMA's are next to impossible to carry out, temperatures in summer easily reach 40°C, and I don't have access to air conditioning. Therefore, I need to keep it safe, and can't consider OCing the 5820K to 4Ghz.

 

I understand most of what I'll actually be doing is single-threaded work, but a lot of what I do is also multi-threaded. However, is it enough to favor going for the slower 6-core? I might sound like I'm deciding for the 5820K, but I'm really not sure.

Which of these two do you think would be the better option for me?

 

Thanks in advance for any replies.

Edited May 17, 2016 by aaronmontero

[Nikolaos M]

I vote for the 5820K in your case. It's single threaded performance is comparable to the 6700K's, but that's not the only thing. Since you are into gpu rendering too, a X99 based system would more preferable in case you wanted to add a second gpu, without limiting the system's expandability in terms of pcie lanes.

 

How much are you willing to pay for this new system? Are there any old parts you want to use building it?

 

Don't worry about oc the 5820K. It wont "feel" a 4GHz frequency as an oc at all. With a good AIO cooler you can run it at 4.3-4.4GHz at a 24/7 basis without issues. I live in Greece and temps here are very high at the summer too. I run a 5960X at 4.4GHz and lower it at 4.2-4.3 during summer. No worries.

[jonasmotiejunas]

why not reading this? http://forums.cgarchitect.com/80150-cheap-16core-xeon-node-pros-cons.html

 

you can get double the performance of 5820k for the same price or cheaper

[numerobis]

Therefore, I need to keep it safe, and can't consider OCing the 5820K to 4Ghz.

 

As Nikolaos said, there is really no risk overclocking a 5820K to 4.0-4.1GHz. Sure every chip is different and if you're really unlucky it is possible that you'll not reach even 4GHz without high voltages. But normally, these "mild" overclocks should be easy achievable with only a slight or even no increase or decrease of voltages.

And the other option would be a per core overclock. I never tried it so far with Haswell-E, to see if it is stable. But you can adjust the turbo clocks based on core usage just like the normal turbo works. So you could set the single core turbo to 4.1-4.3GHz and the all core turbo to maybe 3.8GHz or leave it at default (3.4GHz).

 

And btw... the 5820K is "old" hardware in 2-3 weeks. Broadwell-E should be released at Computex. Better look for the 6800K instead.

Edited May 17, 2016 by numerobis

[aaronmontero]

I vote for the 5820K in your case. It's single threaded performance is comparable to the 6700K's, but that's not the only thing. Since you are into gpu rendering too, a X99 based system would more preferable in case you wanted to add a second gpu, without limiting the system's expandability in terms of pcie lanes.

That's a very good point.

 

How much are you willing to pay for this new system? Are there any old parts you want to use building it?

Well, I'm hoping not to expand too much from what I listed up there if I'm going with the 5820K, as I'm also looking to buy a good monitor at this time (upgrading from a 24" 1080p LCD TN + 900p 19" CFL TN) and it's already getting a bit expensive altogether. I was thinking of using a Hyper 212 Evo heatsink on it, but I wasn't considering the overclock...

 

The parts I would be keeping from my current setup are basically the following:

GPU: Asus Strix GTX970 4GB OC Edition

PSU: Cooler Master G650M, 80+ Bronze

Case: Cooler Master HAF912

HDD: Two HDD drives, I'd be adding an SSD.

 

Don't worry about oc the 5820K. It wont "feel" a 4GHz frequency as an oc at all. With a good AIO cooler you can run it at 4.3-4.4GHz at a 24/7 basis without issues.

Do you think I could pull off something like 3.8 or so on air cooling with the 212, or maybe a Noctua? I've never bought an AIO (or OC'd for that matter) so I don't know just how cool that could keep it.

 

why not reading this? http://forums.cgarchitect.com/80150-cheap-16core-xeon-node-pros-cons.html

you can get double the performance of 5820k for the same price or cheaper

I did, I think it's fantastic for an affordable node. However it's actually much more expensive than the upgrade I have in mind once you consider the rest of the parts (mobo, cooling, memory, power). It doesn't provide as fast single-threaded performance as the options I'm looking at either. It would be a bit of a waste to have it as my workstation, unless I was almost exclusively rendering most of the day, which is hardly the case. Perhaps I'll build something similar down the line.

 

As Nikolaos said, there is really no risk overclocking a 5820K to 4.0-4.1GHz. Sure every chip is different and if you're really unlucky it is possible that you'll not reach even 4GHz without high voltages. But normally, these "mild" overclocks should be easy achievable with only a slight or even no increase or decrease of voltages.

And the other option would be a per core overclock. I never tried it so far with Haswell-E, to see if it is stable. But you can adjust the turbo clocks based on core usage just like the normal turbo works. So you could set the single core turbo to 4.1-4.3GHz and the all core turbo to maybe 3.8GHz or leave it at default (3.4GHz).

Is it possible to overclock the CPU without having to overclock the RAM or GPU, and would I actually need RAM faster than 2133? I've read that anything faster than that is basically pointless in DDR4, but does it present an obstacle to overclocking exclusively the CPU?

[aaronmontero]

And btw... the 5820K is "old" hardware in 2-3 weeks. Broadwell-E should be released at Computex. Better look for the 6800K instead.

I was looking at the wrong chip, apparently the 6800K is pretty much apples to apples with the 5820K. Maybe I should wait... but I don't see much of a reason if it's about the same.

Edited May 18, 2016 by aaronmontero