Hi, This may be a naive or repeated question but could someone please suggest which of SL 5.3 (x86 or x86_64) would be better to dual-boot (with Windows Vista Home and eventually Windows 7) for the Core 2 Duo T6500, 4 GB customised HP laptop whose purchase details are further given below. The machine is for a novice wants minimum update hassles, can flip between Vista and SL easily, and prefers speed, especially at start-up. The owner is  not familiar with Windows Vista (me neither), and I was not impressed by the time it took to boot. Would there be any speed penalty and/or "tweaking penalty" in using x86 instead of x86-64 or vice-versa on this processor? Given the newness of the machine (and so perhaps some of its components may not yet have drivers etc), would waiting for SL 5.4 be worthwhile. If yes, can Troy hasard an informed guess on possible release date/period for SL 5.4? I would be grateful for suggestions William. ------------------[ Specification of HP dvt6 laptop ]--------------------- HP Pavilion Entertainment dv6t customizable Notebook PC • Genuine Windows Vista Home Premium with Service Pack 1 (64-bit) • Intel(R) Core(TM)2 Duo Processor T6500 (2.1GHz, 2MB L2 Cache, 800MHz FSB) • 4GB DDR2 System Memory (2 Dimm) • 320GB 7200RPM SATA Hard Drive with HP ProtectSmart Hard Drive Protection • Intel(R) Graphics Media Accelerator 4500MHD • 16.0" diagonal High Definition HP Brightview Display (1366x768) • LightScribe SuperMulti 8X DVD+/-RW with Double Layer Support • Webcam Only • Wireless-G Card with Bluetooth • 6 Cell Lithium Ion Battery • No Modem