CW, If your iMac has 10.5.8, then you have Mac OS X Leopard. The .8 in 10.5.8 means there have be CW, If your iMac has 10.5.8, then you have Mac OS X Leopard. The .8 in 10.5.8 means there have been 8 updates applied to the base 10.5.0 version.Mac OS X Snow Leopard is version 10.6 which you do not currently own, but can be purchased for $29 from any Apple Store.verview. If you need to purchase Mac OS X 10.6 Snow Leopard, you may order it from this page. The most current version of OS X is OS X 10.10 Yosemite. To learn more, please click here. Note: Some OS X Snow Leopard features require an Apple ID; terms apply.