Answer to: hard drive replacement with SSDThat's simply not true. Go to youtube and pull up any number of videos on older machines with ssd upgrades on sata1.
Answer to: hard drive replacement with SSDA Sata 1 bus supports 1.5 Gpbs, an ssd is a great upgrade. The hard drives can't even come close to pushing the limit of the interface speed. Look at some of the side by side comparisons on youtube in older macs.