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matty1551

macrumors 6502
Original poster
Jul 7, 2009
289
30
I installed a GTX660 a few minutes ago and put it in Slot 2 rather than 1, where my old GFX card was. I figured it might be better temperature wise in slot 2.

However, the expansion slot utility is coming up and telling me that the card is not running at maximum speed.

Do I have to use it in slot 1 to get max speed?

Heres a pic.

fa7vw1.png
 
I installed a GTX660 a few minutes ago and put it in Slot 2 rather than 1, where my old GFX card was. I figured it might be better temperature wise in slot 2.

However, the expansion slot utility is coming up and telling me that the card is not running at maximum speed.

Do I have to use it in slot 1 to get max speed?

Heres a pic.

Image

I think you do have to use slot 1 from what I remember, at least in the older Mac Pro's. Hmmm. Anyone more knowledgable care to comment?
 
I installed a GTX660 a few minutes ago and put it in Slot 2 rather than 1, where my old GFX card was. I figured it might be better temperature wise in slot 2.

However, the expansion slot utility is coming up and telling me that the card is not running at maximum speed.

Do I have to use it in slot 1 to get max speed?

Heres a pic.

Image

Yes, you do need to run the card in slot 1 to get maximum performance. Slot 1 is the only capable slot of running an x16 PCIe lane. Any other slot will happily run it at 8x provided you use the PCIe utility (which you have pictured) to configure it to run at x8. However, Slot 1 is easily the best choice, as it will yield the best performance (x16 bandwidth) and it is physically a double wide slot, so your card isn't blocking access to another PCIe slot.
 
Same suggestion, use slot 1.

As you can see in the PCIe Utility. You choose option 2. That means...

Slot 1 is x16 lane, which is the default slot for high performance graphic card.

Slot 2 is x1 lane, the slowest one.

Slot 3 and 4 are x4 lane. Both run at medium bandwidth.

If you really need to run both cards, choose the 1st option from PCIe Utility.

And then put the new card in slot 1, and the old card in slot 4 (It seems you don't have any other card).
 
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