MacPro RAID card - run at 4x?

[PowerMike G5]

So I have the Mac Pro RAID card and I use it to run a 4 drive RAID 5 (my boot drive is in a Pro Caddy in my 2nd Optical Drive Bay).

It currently is using an 8x PCIE slot, but does anyone know if I can run the card at 4x speed and still not incur a penalty in speed or anything like that?

3 of my 4 slots are taken and all I have left is 1x in the open slot. And I need at least 4x for a video capture card I plan to buy.

 

[PowerMike G5]

Upon further research, it seems that the 2008 Mac Pro's #4 slot is a 4x slot, which the RAID card connects too.

So would it be safe to assume that if I configure the #4 slot in my Mac Pro to 4x, then it should run at the same speed?

 

[kakace]

I have the feeling that a 4x PCIE 2.0 slot has the same bandwidth as a 8x PCIE 1.x slot, but I might be wrong.

 

[PowerMike G5]

well the 4x slot in the new Mac Pro is PCIE 1.0 - the same type of slot as in the older Mac Pro.