PCI x16 vs x4

[damiengajda]

Hi,

I'm wondering how much difference using the x4 slot is compared to the x16 for graphics cards (GTX 900 range)

Does it make a huge difference?

I've got many pc's here with the cards in the x4 slot and if it doesnt make much difference i'd rather leave them as they are

Thanks!

 

[Supahos]

Biggest issue is the 4x slots have to be full length, and also remember it'll need more power from the PCI connector since there won't be as many pins feeding the card from the slot

 

[firefoxx04]

I think nvidia cards support a minimum of x8. AMD cards will work in an x4, however, any card worth using for gaming will likely saturate an x4 slot. You also need to consider that most x4 slots are wired to the chipset and NOT the CPU. For gaming, you want the gpu to have a dedicated link to the cpu. These slots are almost always x8 or x16.

Lastly, x16 slots may only be wired for x4 or x8. It depends on your CPU and motherboard.

 

[Rogue Leader]

Biggest issue is the 4x slots have to be full length, and also remember it'll need more power from the PCI connector since there won't be as many pins feeding the card from the slot

Actually a 16x card will function properly in a short 4x slot, that said short slots on consumer motherboards tend to be 1x slots which you can't use. Anything 4x and up tend to be full length (just that secondary slots while full length are rated at 4x).

That said while the difference between 8x and 16x is minimal, the drop to 4x can have a performance difference. Its enough that Nvidia will not allow SLI on slots slower than 8x. Depending on the slot and board some 4x slots don't go direct to the CPU which can also cause even more of a performance hit.

So yes it makes a difference, I would call it pretty big.

 

[Rogue Leader]

I think nvidia cards support a minimum of x8. AMD cards will work in an x4, however, any card worth using for gaming will likely saturate an x4 slot. You also need to consider that most x4 slots are wired to the chipset and NOT the CPU. For gaming, you want the gpu to have a dedicated link to the cpu. These slots are almost always x8 or x16.

Lastly, x16 slots may only be wired for x4 or x8. It depends on your CPU and motherboard.

Nvidia cards will work in a 4x slot, however SLI requires 8x, while AMD Crossfire will allow x4.

 

[Supahos]

I've seen a few on some builds that were half length was just making sure his were full length. I wouldn't use any GPU without PCI power connectors in a 4x slot. And you're definitely right it will be terrible if it's chipset lanes not CPU lanes

 

[Rogue Leader]

I've seen a few on some builds that were half length was just making sure his were full length. I wouldn't use any GPU without PCI power connectors in a 4x slot. And you're definitely right it will be terrible if it's chipset lanes not CPU lanes

Yeah they are out there, just not common on consumer boards, usually though the slot is open in the rear to accommodate long cards. I've even seen open 1x slots, people use GPUs for mining in them, because they don't need the PCIe bandwidth for that.

Power wise actually the first 11 rows of pins takes care of that, so no matter the length of card they all are capable of pulling the same power. After those the pins are signals and ground triggers only, so there is no worry about power delivery.