Interested to use this amazing sw to mocap single dancers in studio.
Being a NPO we did have uncommon cheap hw, so before starting purchase hw and sw want to be sure all will work together.

- Understood better results for the cost can be obtained using PS3 Eye cameras. The min number is 3? Or need I to consider only odd numbers (4,6)?
- Adding cameras will benefit both range and accuracy?
- The start hw is a laptop (in the future a proper desktop can be purchased, not 100% sure tough), a Lenovo X220 with 8GB RAM, i5-2520m 2.5 Ghz dual core with HT CPU, Intel HD3000 iGPU, + an external GPU Sapphire Radeon HD7950Boost, attached the setup image
- The laptop does have 2xUSB2.0 ports, will be enough to use 3 or more PS3 Eye cameras? Looking at Device Manager did find these controllers:
Intel(R) 6 Series/C200 Series Chipset Family USB Enhanced Host Controller - 1C26
Intel(R) 6 Series/C200 Series Chipset Family USB Enhanced Host Controller - 1C2D
- The internal GPU will be not enough I think both for recording and data analysis, so the external need to be used. Anyone does try the eGPU setup?
- The CPU will be a bottleneck so it's a waste of time trying to use this hw?

Generally, we recommend PS Eye over depth sensors (Kinect and others) because of greater capture area and increased frame rate.
With greater number of cameras you create more points of view, thus preventing tracking errors caused by occlusions. That's why it is better to track more complex motions with more cameras.
3 color cameras is a minimum for the tracking to work at all, but may produce many errors, depending on captured motions. For capturing dances, I recommend at least 5-6 PS Eyes or dual Kinects.

Your laptop looks good for recording with a single first-generation Kinect. You can't use second generation Kinect (which is slightly more accurate), because it requires USB 3.0.
For 3-4 PS Eyes, CPU and memory look OK. 2x USB 2.0 ports look as a possible problem. First, you need USB hubs to even connect more than 2 cameras. Second, both ports may be internally linked to a single USB controller, with second controller used for built-in devices like webcam, network, card reader etc. In this case, you can connect more than 2 cameras, but only with a lower frame rate (30-40 fps). If you have a regular HDD in the laptop, not SSD, then there may also be a problem with disk writing speed during recording.
If you have 1-2 other laptops, you can use the distributed recording feature to record with more cameras.

GPU usage during recording is fairly low, so integrated GPUs are usually sufficient. However, for the tracking process in Mocap Studio, the GPU performance is essential. HD 7950 seems adequate, if it performs as well as when plugged in a regular desktop.

Will check about my USB controller, if both of them are free what kind of USB hub need I to connect 3+3 PS3 Eye cam on mine 2 USB ports?
I did have an msata 120GB internal SSD if that is enough for a 2 min recording.

Any USB 2.0 hub should fit. You'll need a separate hub for each of the laptop's ports to split cameras equally between them.
But again, if both USB ports belong to the same controller, you can't run more than 2 cameras at 60 fps or 3-4 cameras at 30-40 fps.

Disk usage depends on the number of cameras, frame rate and compression options. For instance, for 4 cameras at 60 fps it's about 70MB/s uncompressed, 40-50MB/s with background subtraction and 10-20MB/s with JPEG.

Returning on this topic since we are organizing a new event.
Not an hardware expert, looking at device manager I did find the picture situation.
Looking at the two devices connected on the two available USB ports their properties show: Port_#0001.Hub_#0004 and Port_#0002.Hub_#0004
This mean they did use the same Hub, limiting the connected cameras FPS?

Reading http://docs.ipisoft.com/Cameras_and_Accessories#USB_controllers I got I did have only 2xUSB 2.0 controllers, one of them is used, so I can use max 2 cam.
My laptop did have an ExpressCard 2.0 port capable of USB 3.0 SuperSpeed, using an EC to USB 3.0 adapter might I use this as additional USB controller?
Using 2xKinect 1 will be better?

Yes, an USB controller in the form of ExpressCard will allow you to connect more cameras. 2 ports of laptop + 2 ports of USB ExpressCard = 4 PS Eye cameras (2 per controller) or 2 Kinect v1 depth sensors (one per controller).

Kinects are easier to setup and operate, but they have less frame rate (bad for quick motions), less capture area (about 2x2 meters) and provide worse feet tracking.
Check out the comparison of Kinect vs PS Eye configurations
http://docs.ipisoft.com/Multiple_Depth_Sensors_vs_Sony_PS_Eye_Comparison

So with the event just 3 months away I need to proceed on the topic

Got a "new" desktop PC with: i7-860 CPU (2010 produced, 4-core 2.8Ghz, equivalent to a modern i3), 14GB RAM, same HD7950 GPU, 1 HDD, 1 small SSD (for OS). Does have 2 USB 2.0 hubs (1 used from mouse, 1 free), I can add trough PCIe slot a new USB3 hub. Some questions

- CPU will be enough or it's irrelevant?
- working with 6 cameras better to add another 2xUSB3 port trough PCIe card?
- the working space it's about 3x3 mt wide, too big for 2xKinect v1 (no second PC to use 2xKinect v2) but too small for PS Eye? Maybe using 4 PS Eye?

Hi
CPU looks sufficient for 6 PS Eyes or 1-2 depth sensors. Separate HDD should also handle recording without problems.
I suppose you mean 2x USB 2.0 controllers not hubs. This is enough for 4 PS Eyes at 60 fps or 6 PS Eyes at 40fps (if you have enough USB ports). Adding an USB controller on PCIe card will allow you to get 6 PS Eyes at 60fps. Ensure it's based on NEC/Renesas USB 3.0 chip to avoid compatibility problems with PS Eyes.
Is 3x3m the whole available area for placing cameras? If so, it's rather small both for PS Eyes and depth sensors. You can still try to get 1x2m capture area by placing depth sensors in 2 adjacent corners while an actor is walking beside the opposite wall. As for PS Eyes, you can try placing 3-4 cameras along one wall, and 2 more at the ceiling above an actor looking to the floor.
However it would be better to find a bigger room.