PA is unplayable slow

Hello,

bought and installed PA yesterday using Steam. I tried to play it and it worked about 5–10 Minutes (mostly until first enemy contact). After that PA is becoming unplayable slow and blocks the whole machine until PA gets killed by myself.
Since I kill PA by myself I'm not sure if posting a log is useful (even though: where are they located? )
Im running PA on elementaryOS (Luna) – which is a fork of Ubuntu 12.04.

Code:

Processor Information:
    Vendor:  GenuineIntel
    CPU Family:  0x6
    CPU Model:  0x2a
    CPU Stepping:  0x7
    CPU Type:  0x0
    Speed:  2201 Mhz
    8 logical processors
    4 physical processors
    HyperThreading:  Supported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Unsupported
    SSE41:  Supported
    SSE42:  Supported
   
Network Information:
    Network Speed: 
   
Operating System Version:
    elementary OS Luna (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.2.0-67-generic
    X Server Vendor:  The X.Org Foundation
    X Server Release:  11103000
    X Window Manager:  Mutter(Gala)
    Steam Runtime Version:  steam-runtime-release_2014-04-15
   
Video Card:
    Driver:  NVIDIA Corporation GeForce GT 555M/PCIe/SSE2

    Driver Version:  4.4.0 NVIDIA 331.38
    OpenGL Version: 4.4
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 60 Hz
    VendorID:  0x10de
    DeviceID:  0xdcd
    Number of Monitors:  1
    Number of Logical Video Cards:  1
    Primary Display Resolution:  1920 x 1080
    Desktop Resolution: 1920 x 1080
    Primary Display Size: 15,04" x 8,46"  (17,24" diag)
                                            38,2cm x 21,5cm  (43,8cm diag)
    Primary Bus: PCI Express 16x
    Primary VRAM: 3072 MB
    Supported MSAA Modes:  2x 4x 8x 16x
   
Sound card:
    Audio device: Realtek ALC665
   
Memory:
    RAM:  5930 Mb
   
Miscellaneous:
    UI Language:  English
    LANG:  de_DE.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  57138 Mb
    Largest Free Hard Disk Block:  28711 Mb
   
Installed software:
   
Recent Failure Reports:
   

Any ideas what could cause this problem?

Have you updated your graphics drivers?

Sounds like you're running out of RAM. Have you setup a swap partition?

NVIDIA Driver Version is: 331.38.

I didn't create a swap partition because of askubuntu.com/questions/155244/how-do-i-calculate-a-swap-partition and ubuntuforums.org/showthread.php?t=1033573

Is swap really used by PA?

PA use a lot of RAM. In-game UI use about 2.5GB and game memory usage depends on what planets you load, but it's can be easily pass 4GB mark. So you're just going out of RAM and if OS don't have SWAP your OS dead.

Ok, thank you. After creating 4GB of swap PA runs way better but still lacks after a certain point (~150–200 units).
What else could I do?

There is a problem with the number of units/buildings and planets. If there's more than one planet I can't even start the match.
Is there any solution or some point I missed?

Does it matter that i just played galactic war and only my laptop had to do all the work?