[CentOS] how to use 2 Nvidia Cards in one system

Hallo,

is there a way to use 2 different Nvidia Graphiccards in one system?
The first one is working fine with 3 displays but I want to use 2 more  
displays with the second card.
Do I need two card of the same series (4 or 7) or is there a way to  
mix different series?

Thanks for hints.

Ralf


[root at pcprengellx ~]# lspci
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th  
Gen Core Processor Host Bridge/DRAM Registers (rev 07)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th  
Gen Core Processor PCIe Controller (x16) (rev 07)
00:14.0 USB controller: Intel Corporation 100 Series/C230 Series  
Chipset Family USB 3.0 xHCI Controller (rev 31)
00:14.2 Signal processing controller: Intel Corporation 100  
Series/C230 Series Chipset Family Thermal Subsystem (rev 31)
00:16.0 Communication controller: Intel Corporation 100 Series/C230  
Series Chipset Family MEI Controller #1 (rev 31)
00:16.3 Serial controller: Intel Corporation 100 Series/C230 Series  
Chipset Family KT Redirection (rev 31)
00:17.0 SATA controller: Intel Corporation  
Q170/Q150/B150/H170/H110/Z170/CM236 Chipset SATA Controller [AHCI  
Mode] (rev 31)
00:1c.0 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset  
Family PCI Express Root Port #5 (rev f1)
00:1f.0 ISA bridge: Intel Corporation Q170 Chipset LPC/eSPI Controller  
(rev 31)
00:1f.2 Memory controller: Intel Corporation 100 Series/C230 Series  
Chipset Family Power Management Controller (rev 31)
00:1f.3 Audio device: Intel Corporation 100 Series/C230 Series Chipset  
Family HD Audio Controller (rev 31)
00:1f.4 SMBus: Intel Corporation 100 Series/C230 Series Chipset Family  
SMBus (rev 31)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (2)  
I219-LM (rev 31)
01:00.0 VGA compatible controller: NVIDIA Corporation GM107 [GeForce  
GTX 745] (rev a2)
01:00.1 Audio device: NVIDIA Corporation Device 0fbc (rev a1)
02:00.0 VGA compatible controller: NVIDIA Corporation GT218 [GeForce  
405] (rev a2)
02:00.1 Audio device: NVIDIA Corporation High Definition Audio  
Controller (rev a1)