so i upgraded to ubuntu 14.04 from 12.04 with a usb but i have internet ,my computer is really slow at 1024x768 definition ,everything works super slow ,windows closing and opening and streaming videos ,everything ive used so far.but it works fine at 800x600 definition ,i want it to be fine at the higher definition ,how do i make it run well at 1024x768 ?

in additional drivers nothing shows ,and my computer mirrors by default for some reason ,i tried stopping it from mirroring but most buttons dont want to work and weird glitches happen ,the system doesnt work well when not mirroring , i dont care if it mirrors or not i just want good performance .thank you in advance for any answers !!
here are the computer specs

Processor 1.8 GHz 8032 Intel® Atom™ Cedar Trail Dual Core CPU

RAM 2 GB DDR3

Memory Speed 1066 MHz

Hard Drive 32 GB

Graphics Coprocessor Graphics Media Accelerator HD

Wireless Type 802.11B, 802.11G, 802.11n

Number of USB 2.0 Ports 4

Brand Name Asus

Item model number EB1030-B003L