Xeon 10-core v Xeon 12-core - advice please!

[alexyork]

Hi folks,

I'm after some help please. I'm speccing up a new dual-xeon workstation and have come to a point where I need to decide between these two configs for VRay rendering:

- Intel Xeon E5-2670 V3, S2011-3, Haswell, 12 Core, 2.3GHz, 30MB cache
- Intel Xeon E5-2687 V3, S2011-3, Haswell, 10 Core, 3.1GHz, 25MB cache

Now, the 12-core runs at a slower per-core speed, so will be worse for unthreaded/poorly-threaded applications, but has 2 more cores (4 in total across the machine), so 8 extra threads in total. It's also almost £1000 cheaper than the 10-core.

According to many benchmarks they appear to be very close in terms of speed performance, but the 12-core is almost £1000 cheaper in this system, and perhaps might be faster and more efficient overall? It seems to be the best value-for-money option here.

Which would you go for?

Also, I am aware of Autodesk's NUMA issue with >64-core systems so these ones should be fine, right? It would either be 40-core or 48-core in total.

Thanks!

[theedge]

If you simply multiply the frequencies by the number of cores the E5-2687 V3 delivers a bit more : 31 GHz vs 27.6 GHz
Now how much difference does that make in real life, I have no idea. I guess the <4 GHz difference might make a great difference for a machine rendering 24/7

[alexyork]

If you simply multiply the frequencies by the number of cores the E5-2687 V3 delivers a bit more : 31 GHz vs 27.6 GHz
Now how much difference does that make in real life, I have no idea. I guess the <4 GHz difference might make a great difference for a machine rendering 24/7

This is kind of what I was thinking, given that these processors are the same architecture, so it should be reasonable to compare them in terms of raw frequencies. However I'm wondering about efficiencies with Vray. Perhaps it works more efficiently and therefore more quickly with slower threads but more of them, than fewer threads that are faster. I'm wondering if Vlado or anyone from Chaos has any direct experience with this and can chime in.

What I have just noticed... according to Anandtech, the 2670 can turbo boost up to 2.6ghz across *all* 12 cores, whereas the 2687W can only boost up to 3.1 across all of its cores... so actually the 2670 could have a raw frequency of 31.ghz V the 2687W of only 31.0ghz... so if they are equal or almost equal there, but it's £1000 cheaper....

See these:





Cheers,

[alexyork]

Incorrect! Please ignore.

[alexyork]

Retracted!!

Yet more confusion. It turns out that Intel's rep on the phone this morning was incorrect, and Anandtech are in fact correct.

See below:



So it's clear from this Intel table that the 2670 12-core runs at 2.6ghz per core when all 12 cores are loaded and that the 2680W runs at 3.2ghz per core when all 10 cores are loaded. This creates a general comparison of 31.2ghz v 32ghz - so almost identical. Plus it's likely that more cores = better when talking about highly threaded applications like vray, plus £1000 cheaper. So the 12 core is the way to go.

[vlado]

Heh that's interesting that more cores at lower clock speeds are cheaper.

Best regards,
Vlado

[alexyork]

Heh that's interesting that more cores at lower clock speeds are cheaper.

Best regards,
Vlado

Indeed! In your experience, Vlado, would you recommend going with the 12 over the 10, given this?

[super gnu]

can anything be done with regards to overclocking on those 12 core jobbies?

[alexyork]

can anything be done with regards to overclocking on those 12 core jobbies?

Apparently their multipliers are locked, so any overclocking would have to be done using BCLK and would be extremely mild, which is not ideal, rendering it more or less a "no", or so I'm told.

[super gnu]

a small bclk adjustment over 12 cores should make a fairly meaty difference wether you can get a dual mobo for them with bclk adjustment in the bios is another matter.

[alexyork]

a small bclk adjustment over 12 cores should make a fairly meaty difference wether you can get a dual mobo for them with bclk adjustment in the bios is another matter.

All of the builds that I've been quoted from various places today are using the same Asus Z10PE-D8 WS 2x S2011 motherboard, and I have no idea if it allows for overclocking the bclk at all. I'm asking one of the vendors now, and will report back here with my findings. Even a tiny boost, as you say, could be worthwhile, as long as stability is not sacrificed. Maybe 2.6ghz stock or so...

[super gnu]

i did a quick google.. seems "modest" adjustment is about right.. from what i could see you can change the bclk by about 3mhz. even over 12 cores thats not gonna do diddly squat.

[alexyork]

i did a quick google.. seems "modest" adjustment is about right.. from what i could see you can change the bclk by about 3mhz. even over 12 cores thats not gonna do diddly squat.

Indeed, and it would invalidate the warranty with the vendor as well, so I'll be leaving it alone.

[vlado]

Indeed! In your experience, Vlado, would you recommend going with the 12 over the 10, given this?

Unfortunately I don't have any experience comparing such machines. I would generally prefer a smaller number of faster cores, but if the final performance is the same then I guess I doesn't matter.

Best regards,
Vlado

[SaY]

Performance will be very close. I would go with more cores for less $$. Keep in mind that ECC DDR4 ram is not cheap..

You won't get any NUMA or 64 thread limit problems with 2670v3. I have 14 and 18 core xeons. 14 core work well, with 18 you need workaround because pair of those give you 72 threads. Hopefully Vlado and his team will fix it soon.