一、据说双显卡能提升显示性能，在ubuntu下不安装私有驱动，是不是没啥效果？
二、如果要连接两个显示器。比如，一个显示正常桌面，一个显示虚拟机窗口。要达到这样的目的，怎么设置？
下面是lshw -numeric -class video的输出结果：
*-display
description: VGA compatible controller
product: Oland PRO [Radeon R7 240/340] [1002:6613]
vendor: Advanced Micro Devices, Inc. [AMD/ATI] [1002]
physical id: 0
bus info: pci@0000:01:00.0
version: 00
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
configuration: driver=radeon latency=0
resources: irq:31 memory:e0000000-efffffff memory:f7d00000-f7d3ffff ioport:e000(size=256) memory:f7d40000-f7d5ffff
*-display
description: VGA compatible controller
product: Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [8086:412]
vendor: Intel Corporation [8086]
physical id: 2
bus info: pci@0000:00:02.0
version: 06
width: 64 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list
configuration: driver=i915 latency=0
resources: irq:30 memory:f7800000-f7bfffff memory:d0000000-dfffffff ioport:f000(size=64)
