Anyone got a sandybridge yet?

[Tangled-Universe]

So, with the B3 Revision being out now there's a reason less to not buy a Sandy Bridge.

Who's having one now?
There are still no SB benchmarks on the benchmark site, but I guess/hope it will finish the benchmark ~6 min.

I'm configuring a new PC for the coming 3 years (at least):

Fractal Design Define R3
Be quiet! Straight Power BQT-E7-550W
ASUS P8P67 Rev. 3.0
Intel Core i7 2600K / 3.4 GHz (perhaps with a better cooler to OC it)
16 GB Kingston ValueRAM
ASUS EAH6970/2DI2S/2GD5 GPU (not sure at all, as I would like to play games, but already haven't much time for TG2, let alone games!)
OCZ Vertex 3 Series 120GB SSD (on pre-order available)
Samsung SpinPoint F3 1TB   
Sony Optiarc AD-7260S   DVD-burner

Costs me a limb, but definitely worth it I think.

[Zairyn Arsyn]

(nope, not yet)
i had been trying decide if i should go ahead and get a socket 1155 sandybridge pc or wait for the socket 2011 sandybridges.
a six core sandybridge sounds sounds a bit temping, i know 1 at least one TG2 user uses a six core i7.

though i could more likely afford a 1155 sandy bridge system.

i just found out avadirect.com is offering 1155 barebones configurations. (its slightly cheaper than getting a regular configuration)

[Tangled-Universe]

I've been thinking about a six-core machine as well, also the LGA2011 socket, but that won't be available before end of the year, if not 2012.

Besides that, TG2 doesn't scale that well beyond ~5 threads, so having 12 potential threads available isn't that much of an advantage anymore.
Unless you render with two instances at once of course.

[FrankB]

Besides that, TG2 doesn't scale that well beyond ~5 threads, ..

I'm not sure how true that really is. I mean of course there's a point with multi-threading where the communication overhead between threads will eat up performance advantages. But I reckon that 2 threads per core does give a sizeable advantage even with a 6 core CPU. Now admittedly, I'm guessing here, but frankly I would be surprised if anyone with a six core CPU would voluntarily tune down #threads to below 12 (with HT present of course).

[Zairyn Arsyn]

i'm thinking i might just get a 1155 socket sandybridge, dont know if i would be able to afford that or not.
i've been saying since last summer i wanted to upgrade... getting tired of holding things back.
need to catch up on current hardware for gaming too,

[Tangled-Universe]

Besides that, TG2 doesn't scale that well beyond ~5 threads, ..

I'm not sure how true that really is. I mean of course there's a point with multi-threading where the communication overhead between threads will eat up performance advantages. But I reckon that 2 threads per core does give a sizeable advantage even with a 6 core CPU. Now admittedly, I'm guessing here, but frankly I would be surprised if anyone with a six core CPU would voluntarily tune down #threads to below 12 (with HT present of course).

Well I think you're guessing here indeed?

Just try this:

- Make a simple scene and make sure render-heavy elements aren't constricted to one or two buckets. Render it at decent resolution and quality (720x480 @ 0.7 for instance).

- Render it with 1 thread, record time
- Render it with 2 threads, record time
- etc. etc.
- Render with 4 cores 5 threads, 6 threads etc. etc.

I'm pretty sure linearity stops at around 4-5 threads
In some cases the overhead is so big that having more threads is actually slower than having less.
I can't recall that threshold, it's on the other forums Frank.

Maybe in the near future I'll work on a 6-core HT CPU for a little while and test this myself, as it is important to know to optimize workflow (for production).

Cheers,
Martin

[Tangled-Universe]

i'm thinking i might just get a 1155 socket sandybridge, dont know if i would be able to afford that or not.
i've been saying since last summer i wanted to upgrade... getting tired of holding things back.
need to catch up on current hardware for gaming too,

Where do you live?

If you live in the US or can buy in the US then prizes are pretty good.
The system I mentioned above is ~1300 euros...that's roughly 1500 dollars.
I suppose in the US you can buy a similar system for 1100 dollars.

[cyphyr]

Well I've been using a hex core i7 970 running at 12 threads at work and it is indeed much faster than my home rig (quad core i7 920 running at 8 threads).
This is in no way a definitive test since there are other variables at play. The hex core is oc'd and has a shed load of ram, features my home rig lacks ;(
I did try the default benchmark scene and the difference was not that great however. I think this is highly scene dependant but when I get the time I'll run some more definitive tests. I think the biggest difference is simply that the hex has so much more room to play.

Richard

[Zairyn Arsyn]

US (Florida) - the town i'm addressed to is called Havana, & i once told someone i was from Havana, and they thought i was from Havana, Cuba

for prices, it varies, depending on configurations/setup and where you buy from.

i'm thinking i might just get a 1155 socket sandybridge, dont know if i would be able to afford that or not.
i've been saying since last summer i wanted to upgrade... getting tired of holding things back.
need to catch up on current hardware for gaming too,

Where do you live?

If you live in the US or can buy in the US then prizes are pretty good.
The system I mentioned above is ~1300 euros...that's roughly 1500 dollars.
I suppose in the US you can buy a similar system for 1100 dollars.

[jo]

Hi,

I just thought I'd chip in on the scaling issue as I looked into this in some detail near the beginning of the year. The Windows version should show continuously improving performance up until the point where you go from real cores to hyperthreading cores. At that point performance will still improve but at a slower rate. If you take my dual quad core machine (8 real cores, 8 hyperthreading cores) using 16 threads is appreciably faster than 8 threads but it's not twice as fast.

It's not really true that scaling falls away after 5 threads as Martin says. It will depend on your processor. The point at where scaling falls away really does seem to be at the point where real cores turn into hyperthreaded cores, and this is understandable because hyperthreaded cores are not full cores and are a lot slower. As above, while the scaling does fall away you can still get worthwhile savings in render time. I've attached a graph showing ideal scaling vs the actual scaling on my machine. The scene used was a modified version of the 3D Speed Machine benchmark. I'll give a reminder again that hyperthreading is being used after 8 threads.

Looking at the graph you can see that there is still room for improvement with scaling but it's actually not too bad. Even with hyperthreading a 16 core render is about 18% faster than an 8 core render, which is far cry from being twice as fast but that's never going to happen with hyperthreading anyway.

The Mac version currently gets slower when you move from real cores to hyperthreaded cores. Right now I would recommend sticking with the number of real cores you have for rendering. The good news is that the next release is vastly improved in this regard and it has performance parity with the Windows version.

I will insert the usual caveat of this potentially being scene dependent :-). I should say that using Raytrace Objects and Atmosphere can be a help with scaling.

Regards,

Jo

[Oshyan]

18% is actually about average for hyperthreading performance improvement (when I say "average" I mean across applications, not average for TG2 necessarily).

- Oshyan

[Tangled-Universe]

Hi Jo,

Thanks for proving me wrong

It was a bit dense of me to forget the issue of HT performance comparison.
Thanks for the heads up on this and the clear graph. Very useful!

Actually makes me doubt a little bit again whether I should go for a Sandy Bridge 2700K or an i7-970??
What do you think?

Cheers,
Martin

18% is actually about average for hyperthreading performance improvement (when I say "average" I mean across applications, not average for TG2 necessarily).

- Oshyan

Indeed, didn't took that into consideration in my last few posts

[cyphyr]

I wonder what the performance hit/bonus would be to run two instanced of TG in parallel would be?

Richard

[freelancah]

I've been thinking about a six-core machine as well, also the LGA2011 socket, but that won't be available before end of the year, if not 2012.

Besides that, TG2 doesn't scale that well beyond ~5 threads, so having 12 potential threads available isn't that much of an advantage anymore.
Unless you render with two instances at once of course.

But you could do this http://smattila.pp.fi/3D/Rendering.jpg except with 1 machine! I find out I'm constantly running out of CPU power even tho I have i7 and q9400 at my displosal, lol

[Oshyan]

I'd still go for Sandy Bridge 2600k, unless the price difference really doesn't matter to you (several hundred dollars from what I can see). Not only does the 2600k have higher clock rate per core than the i7 970, but it also improves performance clock-for-clock over 1st gen i7. Granted having 2 whole more physical cores (along with 2 HT threads) on the 970 would help a lot. But if you really want 6/8 core and price is less a concern you might just want to wait for later this year when the 6/8 core versions of Sandy Bridge come around.

- Oshyan