Will pci x16 slot running in x8 mode bottleneck 8600 gt video card?

I'm thinking about buying an 8600 gt but my motherboard sucks and the pci x16 slot only runs in x8. Will the limited bandwith or whatever the x16 means bottleneck the 8600 gt? I'll probably buy the card no matter what cause its only $46 after $50 rebate and I'll probably get a new motherboard in a year or so but either way I'd like to know. Let me know what you think,

thanks|||Yes.