I purchased this Asus EeePC 900 from eBay. The 16 GB SSD is insanely slow, even just navigating Windows XP. I heard that the 4 GB flash on the motherboard is twice
EeePC 4GにSSDを増設する
Eee PC S101 の内蔵SSDを mSATA SSD に換装 : soltec 工房
ASCII.jp:Eee PC 900を72GBに! アイ・オーの増設SSDを試す (1/3)
128GB RunCore SATA 70mm Mini PCI-e PCIe SSD for ASUS EEE PC 900, 900A, 901 and S101