E5-2643 4-core 3.30Ghz or E5-2670 8-core 2.6Ghz?

[Streetwise]

I've been reading this article about "building a 32-Thread beast" and am intrigued by such a low cost for Xeon E5-2670 C2 CPU's ($70ea).

I'm on an HP Z820 workstation with dual E5-2643 CPU's. I have yet to find motherboard specifications for the different chip, but I suspect it would work, given that both are Sandy Bridge and were released on the same date.

My question is in terms of render speed: E5-2643 4-core 3.30Ghz or E5-2670 8-core 2.6Ghz. The E5-2670, even though less Ghz, has twice the cores, and twice as big of an L2 and L3 cache as the E5-2643.

[mitviz]

I've been reading this article about "building a 32-Thread beast" and am intrigued by such a low cost for Xeon E5-2670 C2 CPU's ($70ea).

I'm on an HP Z820 workstation with dual E5-2643 CPU's. I have yet to find motherboard specifications for the different chip, but I suspect it would work, given that both are Sandy Bridge and were released on the same date.

My question is in terms of render speed: E5-2643 4-core 3.30Ghz or E5-2670 8-core 2.6Ghz. The E5-2670, even though less Ghz, has twice the cores, and twice as big of an L2 and L3 cache as the E5-2643.

would also love to know, i see alot of them on ebay for great prices and am not sure but i think they can be used in a dual cpu setup which would be fantastic

[hoch5]

Easy question, easy answer.

By multiplying the 4 cores by 3.3Ghz you end up at 13.2Ghz.
8 cores multiplied by 2.6 Ghz equals 20.8Ghz.

That gives you just rough numbers, not taking in account possibly diffrent turbo states and so on.

So, get the 8 core

[Streetwise]

I've found out more on this topic since yesterday and apparently its not so simple as that. The rule of thumb for scalability in a system is Amdahl's law, and it's both task dependent and highly theoretical. Interactive work as a workstation is much heavier in single threaded computations, thus higher clock rates of the E5-2643 would be best. But rendering tends to profit from many cores because of its high multithreaded nature. So what I'm hearing as I explore this is that the E5-2643 will make for a better workstation, the E5-2670 a better rendering slave. BUT I think I'm going to go ahead and try it out as there doesn't seem to be a clear cut answer on it.

[hoch5]

Dealing with single threaded tasks still is a problem in 3ds max, sure enough. Taking a look on the daily average workflow, only here and there I'm starring at the screen waiting for something to finish that is obviously not running on multiple cores. It does, and I could go nuts about it sometimes.

On the other hand, being able to get a faster preview of the rendering on your local workstation, saves you a lot of time achieving the result you're looking for. This especially is the case with the progressive image sampler.

[Streetwise]

So I just upgraded dual E5-2643 CPU's with dual E5-2670 CPU's that I got used for $58ea. Even though the clock speed is slower (3.30Ghz vs 2.6Ghz), I got a huge performance boost from going from 16 threads to 32. On this test, I went from 1:39, to 1:01 (embree on). Tremendous bang for the buck I'd say!

[mitviz]

So I just upgraded dual E5-2643 CPU's with dual E5-2670 CPU's that I got used for $58ea. Even though the clock speed is slower (3.30Ghz vs 2.6Ghz), I got a huge performance boost from going from 16 threads to 32. On this test, I went from 1:39, to 1:01 (embree on). Tremendous bang for the buck I'd say!

are those from ebay?

[Streetwise]

are those from ebay?

Yes. http://ebay.to/29dPXUo

Turns out "make an offer" to the seller is like maybe offering .10 cents less than what he's asking... I had to laugh at that.

[mitviz]

haha, great you baught them! i am now looking to do the same!

[mitviz]

Yes. http://ebay.to/29dPXUo

Turns out "make an offer" to the seller is like maybe offering .10 cents less than what he's asking... I had to laugh at that.

what's the rest of your settup look like?

[Streetwise]

what's the rest of your settup look like?

You won't go wrong for that price!

HP Z820 (bought off-lease for $1300 on ebay)

HP Z820 Tower 2x Xeon Quad Core 2643 3.30 GHz
600GB Drive
96 GB RAM
DVD
Win 7 Pro
1125w PSU

I think it came with a Quadro FX4800, But I had an old 5000 that I put in for RT GPU and a GTX480 for the UI. Also, I bought a Samsung 850EVO 500GB drive for work-in-progress. There's a special caddy tray that will hold them.

I just picked up two GTX780 6GB cards off of eBay that I'm planning to put in next week to see how it goes with better RT GPU. I'll move the Quadro 5000 to the UI. (If you run three cards, its essential that you have the larger 1125w supply. I think they also come with 850w or something.)

Anyhow, I couldn't be happier with it for a 3yr old PC, especially with those kinds of render times. Wow.

Do you have an HP as well?