Computer requirements...

[Lambo]

Hello all, this is a subject that has been covered quite extensively here but there are still too many questions unanswered since it is pretty complex and no one has enough time to test every possible configuration.
I have read every post here concerning this topic but I still have some doubts.
If I understood correctly, the basics that we know so far are these:
The more memory the better. Small projects (no more than 30 or 40 14 Mpix pictures) will do with 32 to 64 GB of RAM and bigger projects will need more than 256 GB of RAM. This applies specially for using the Ultra High setting when building the Dense Cloud.
Video Cards: AMD cards are much faster than Nvidia ones for PS. If you can afford 2 or more even better. Gaming cards like the HD7950 are better than workstation ones like the FireGL ones.
NOW, CPU comparisons (and here are my questions) I understand that the more cores the better since when you disable a core per GPU for better processing, the more cores you have, the smaller the loss in processing from the CPU right?
I read somewhere that there were some problems with the Dual CPU configurations? I can not find that thread anymore. Does that mean that Dual Xeons could be problematic?
How much does the GHZ power of a CPU matter here?
So that brings me to the main question I have after I have been doing lots of research between possible CPU's to buy:
I have the choice between the i7 3930K processor and Dual Xeon 2620 processors.
Now the question is, the i7 3930K slightly overclocked has the same power as Dual Xeon 2620 but has the advantage of being just 1 CPU and that lowers some latencies, etc.
The Xeon has the advantage of using a motherboard that can handle up to 512 GB of RAM compared to 64 GB of the i7.
Which one will be the best one to get in this case?
Well I think these are more than enough questions for now ...
Thanks a lot for your insights in this matter.
Leo

[Marcel]

The more memory the better. Small projects (no more than 30 or 40 14 Mpix pictures) will do with 32 to 64 GB of RAM and bigger projects will need more than 256 GB of RAM. This applies specially for using the Ultra High setting when building the Dense Cloud.

Lots of memory is mostly needed for the Mesh generation stage. The Dense cloud stage does not need that much memory. (Although I did have it run out of 64GB memory with 400+ 36MP photo project).

Dual CPUs are not giving problems, but the latest model Xeons are just not as fast as you would expect them to be (compared to the i7 consumer versions). But they offer support for more than 64GB memory, so that is a big benefit.

[Lambo]

Thanks Marcel, that is kind of what I got from the other threads I have been reading.
But the original question still remains, which would be the best choice for someone that works normally with between 70 and 100 16 Mpix shots?
The Dual Xeon 2620 or the i7 3930K ?
Does the fact that I would have only a max of 64 GB RAM with the i7  hinder my calculation times too much for that many photos?
Thanks in advance for your help.
Leo

[Lambo]

Something very cool that may be of use for a lot of people, I just found this motherboard in Newegg that is made for the Core i7 chips and supports up to 128 GB of RAM
I still have to check some reviews and make sure it doesn't have any problems but it looks promising.
That would make my decision much easier since now I don't have to go with the Xeons anymore.
Leo

[Wishgranter]

Lambo with the board supporting 128 GB is problematic, the i7 memory controller is not  prepared to address more than 64  GB of ram, its a hardware limitation. Intel is segmenting the CPU so if need more than 64 you need XEON ( pricey part )

and for 128 GB you need 16 GB RAM modules that as far i know are still NOT on market.

for you need im recommend http://www.anandtech.com/show/7613/asus-p9x79e-ws-review its 64 GB RAM and even slight OVERCLOCKING of XEONS, but read it carefully.

[David Cockey]

A superfast computer with very large amounts of memory is not absolutely required for processing relatively large projects.

I routinely process projects with 200 to 750 15MP photos on a computer with:
CPU - Intel I7 3770 Quad Core
GPU - AMD 3770, 3 GB memory (PhotoScan only uses 2GB)
Memory - 16MB, DDR3-1600
OS - Windows 7

Projects are "arbitrary" geometry, high accuracy is used for alignment, medium or high resolution for dense cloud generation with ultrahigh for small areas as needed.

Typical dense cloud generation performance:
Device 1 performance: 111.838 million samples/sec (CPU)
Device 2 performance: 328.192 million samples/sec (Capeverde)
Total performance: 440.03 million samples/sec

I divide the project into chunks as needed to stay within the memory limitation. Each stage may have a different number of chunks. For dense point cloud generation the bounding box is carefully set, and with large numbers of photos the object is divided into several overlapping chunks.

[James]

Same here, I am actually processing a project with ~1000 24MP images. A highly arbitrary structure indeed with similar specs to you:

i7 2700k
16GB ram
gtx 580
win7 64

i can manage about 100 photos per chunk and build dense cloud on high in between 0.5-4 hours each depending on content.

I do not have gcps for this dataset so re-alignment of chunks is interesting. i spent some time aligning ~600 on high which i am pretty happy with and i think processed all in one chunk. i use this chunk to reference/align all my other sub chunks using camera based alignment.

*edit* the camera based alignment is required because i never get the chunks right first time and always end up swapping images in and out and re-aligning within chunks, etc etc *edit*

still all this 'chunkwork' is not such a lot of fun and so i am looking at the possibility of a 128-256gb beast.

it's definitely worth doing it the hard way first with a lower spec to learn all these little tricks, because you can never have enough ram...

[Lambo]

Thanks all of you for your responses. But to make sure, I understand the limitation form the i7 CPU's but why do they advertise that board in Newegg as made for the i7?
Also does this mean that this memory  http://www.newegg.com/Product/Product.aspx?Item=N82E16820239638  is not good for the i7 systems? It seems to be the same as the ones I find that are smaller. Does it have some other specs I am not aware of? It is sold as server memory but seems to be the same as the other ones.
Well that is good to hear that you guys are being able to work without having that much memory, so I should be good for now if I can get 64 GB RAM. I have to get the money now
Thanks again...
Leo

[Lambo]

Wishmaster, I think I found it, is it the fact that those memory stick are registered and they have to be unbuffered?
Leo

[Lambo]

Sorry, that's funny I called you Wishmaster instead of Wishgranter

[Wishgranter]

:-DDDDDDD

Yes there are the RAM "configs" that can be used, i7 ( consumer  CPUs ) are mostly limited to the 32 or 64 GB as no proper 16 GB modules exist.

So if need to go over 64 GB need a dual CPU config.

best and fastest solution would be the board as i linked here with proper CPU, but it will cost a lot, from my perspective try to build single CPU setup, i7 3xxxK series, watercooling + overclocking up to 4,5-4,9 stable 24/7 and put there 64 GB ram. This will be the fastest and "cheapest" solution for you. Later can start thinking on Dual Xeon when get more money together.....   

[Alexey Pasumansky]

Hello Leo,

If 64 GB will be enough, I'd rather recommend to use six-core i7 4960X, 3.60 GHz processor for faster processing (note that low frequency will result in slower processing speed). In case more RAM is required for your standard tasks you can consider single-socket Workstation: http://www.agisoft.ru/forum/index.php?topic=1808

Thread about dual-Xeon workstations: http://www.agisoft.ru/forum/index.php?topic=1330.0

And here is thread about >40 core systems: http://www.agisoft.ru/forum/index.php?topic=1875.0
It works fine on Linux servers, but performance results even fall when more than 25 cores are utilized, but I hope Florent will share his experience with these systems in that thread.

[Wishgranter]

He has some interesting results, hope Florent post them self......

[florent.dallot]

Hello,

We carry benchmark for a customer who needs a very large processing capacity (>3000x10MP). We try to find the best configuration ... A lot of core is not the solution today ! see graph.
We have better result on Dual Xeon with 2x Nvidia Grid K2
We should test Xeon Phi this week.

[mr map]

Whoa!! 

Guys, be really careful when configuring your combo of motherboard, CPU and MEMORY!
I became cautious after reading what Ian wrote here:
http://www.agisoft.ru/forum/index.php?topic=1868.msg9990#msg9990
And you can see my posts later in the same thread.
What really got me suspicious was this: http://www.anandtech.com/show/6068/lrdimms-rdimms-supermicros-latest-t
 

I am currently about to purchase a dual Xeon 256 workstation and today my dealer got answer from ASUS regarding memory configuration on the ASUS motherboard I intended to buy:

"Full equipped DIMMs are reducing the speed.
The speed is also depending on the memory Voltage, but also the Ranks of the Module.

KVR13LR9Q4/32 can run @ 1.35V/1.5V and is Quad-Rank.
8pcs in Z9PE-D8 WS will reduce the speed to 800MHz."

800MHz! 

I was opting for:
http://www.asus.com/Motherboards/Z9PED8_WS/#specifications
http://ark.intel.com/products/76161/Intel-Xeon-Processor-E5-2687W-v2-25M-Cache-3_40-GHz?q=Intel%20Xeon%20E5-2687W%20v2
http://www.kingston.com/dataSheets/KVR13LR9Q4_32.pdf

But now I will have to rethink.
Any suggestions welcome.

Lambo, you might not run into this problem if you stay within 64GB, but anyhow, have it in mind and check it up before you order!