Qualidade de vídeo ruim ao reproduzir filmes

[ubu4ever]

Tenho um netbook Acer One 722, rodando Xubuntu 12.10 x32, e estou notando que a qualidade dos filmes não está muito boa. Em cenas paradas a imagem fica perfeita, mas em cenas de velocidade, a imagem fica cortando. Nos testes usei o SMPlayer e o VLC. Tentei várias saídas XV, X11, gl, gl2, etc... Também notei que uma saída pode ficar perfeita em um filme mas não em outro, exemplo: assisti um filme no SMPlayer com saída gl2 e ficou ótimo, porém para outro filme a gl2 não fica boa, aí tenho que mudar para a XV.

Tenho os drivers proprietários da AMD instalados. Configuração do netbook:
AMD Dual-Core C-60 1Ghz/2GB de RAM/Radeon HD 6290

lspci

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00:00.0 Host bridge: Advanced Micro Devices [AMD] Family 14h Processor Root Complex
00:01.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Wrestler [Radeon HD 6290]
00:01.1 Audio device: Advanced Micro Devices [AMD] nee ATI Wrestler HDMI Audio [Radeon HD 6250/6310]
00:11.0 SATA controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 SATA Controller [AHCI mode]
00:12.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
00:12.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB EHCI Controller
00:13.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
00:13.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 USB EHCI Controller
00:14.0 SMBus: Advanced Micro Devices [AMD] nee ATI SBx00 SMBus Controller (rev 42)
00:14.2 Audio device: Advanced Micro Devices [AMD] nee ATI SBx00 Azalia (Intel HDA) (rev 40)
00:14.3 ISA bridge: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 LPC host controller (rev 40)
00:14.4 PCI bridge: Advanced Micro Devices [AMD] nee ATI SBx00 PCI to PCI Bridge (rev 40)
00:15.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB700/SB800/SB900 PCI to PCI bridge (PCIE port 0)
00:15.2 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB900 PCI to PCI bridge (PCIE port 2)
00:15.3 PCI bridge: Advanced Micro Devices [AMD] nee ATI SB900 PCI to PCI bridge (PCIE port 3)
00:18.0 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 0 (rev 43)
00:18.1 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 1
00:18.2 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 2
00:18.3 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 3
00:18.4 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 4
00:18.5 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 6
00:18.6 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 5
00:18.7 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 7
06:00.0 Ethernet controller: Atheros Communications Inc. AR8152 v2.0 Fast Ethernet (rev c1)
07:00.0 Network controller: Atheros Communications Inc. AR9485 Wireless Network Adapter (rev 01)