Theoretical speed from Sata600 controller in PCIE v2x?

[dax trajero]

So I have a motherboard with PCI-Express v2 and Sata 300 built in.

I'd like to buy a new SSD - Samsung 840 Pro to replace my old OCZ Vertex 2

Question
I have a spare Sata 600 controller (Startech PCI-E x1)
What's the theoretical performance I'll get if I plug the new SSD into it ?

To recap:
PCI-E x1 is 500MB/s
SATA 600 is 600MB/s

I realise the new SSD will be restricted by my set up, but by how much ? Will it get near to the 500MB/s the PCI-E socket offers? I realise this is all a bit theoretical but I'm curious to know, before buying the Samsung.

 

[alvine]

pcie x1 can handle 250MB/s

 

[dax trajero]

pcie x1 can handle 250MB/s

Depends on the version of PCI-E

Version 1 = 250 MB/s
Version 2 = 500 MB/s (this is mine)
Version 3 = 1 GB/s
Version 4 = 2 GB