PCI-E 16x - (2x) 8x

[CrazyArsedMonky]

Hello again folks!

I thought i was ready to order my new rig - however i have a niggle at the back of my head. I am getting the below components;


Asus GeForce GTX 670 DirectCU II 2048MB GDDR5 PCI-Express Graphics

Asus Z77 Sabertooth Intel Z77 (Socket 1155) DDR3 Motherboard

Intel Core i5-3570K 3.40GHz (Ivybridge) Socket LGA1155 Processor (77W) - Retail

Corsair Graphite 600TM Midi Tower Mesh Windowed Case - Black

Crucial M4 240GB 2.5" Solid State Hard Drive

Corsair HX 850W ATX Modular SLI Compliant Power Supply

Corsair Vengeance Slimline 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit

Prolimatech Megahalems Rev C CPU Cooler (Socket 775/1155/1156/1366/AMD AM2/AM3/AM3+)

Pioneer 24x Internal DVR-S19LBK DVD Rewriter


My question originates from the intel website... It says it has 3x PCI Express Configurations, 1x16, 2x8, 1x8+2x4. If i have 2 PCI-E components (GPU + Soundcard) will it default to 2x8; if so will it impact GPU performance??

Sorry if this is a stupid question

 

[Rusty0611]

Won't impact performance at all. You'll have it in a PCI-E x1 slot anyway won't you do will run at 16x. However even at 8x it'll have no impact.

Enjoy.

 

[CrazyArsedMonky]

Cheers Rusty! Common sense prevails then. I didn't want to limit the possible bandwidth of the GPU.

Does anyone know the typical B/W that modern cards run at?

 

[Snodge]

Won't impact performance at all. You'll have it in a PCI-E x1 slot anyway won't you do will run at 16x. However even at 8x it'll have no impact.

Enjoy.

To too sure on SLI but I certainly noticed a difference when using my 670 in a x8 instead of a X16 even though both of my slots are x16 it was weird however the heaven benchmark score was about 100 lower )

 

[OpenToSuggestions]

Have a Google there is a review of a 6950 somewhere running at 16x, 8x, 4x, 2x, 1x.
I think 8x lost 1% performance over 16x and 1x lost way under 50%!

Even today, 16x is not really needed. When 32x comes out it will all the promotional talk as it is a selling point, even though it doesn't actually do anything! I don't think a card exists that maxes out 16x.

 

[Orcvader]

On your board stick the 670 in the top PCI-E x16 slot.

The third PCI-E x16 slot is controlled by the Z77 chipset, and runs in x4 mode (unless you plug in anything in any of the x1 slots). So you won't lose any of the x16 lanes to the GPU when you plug in a soundcard to the lowest x16 slot.

 

[OpenToSuggestions]

On your board stick the 670 in the top PCI-E x16 slot.

The third PCI-E x16 slot is controlled by the Z77 chipset, and runs in x4 mode (unless you plug in anything in any of the x1 slots). So you won't lose any of the x16 lanes to the GPU when you plug in a soundcard to the lowest x16 slot.

I think in 4x mode the 6950 lost something like 3% . I wouldn't worry about it .

 

[Orcvader]

I think in 4x mode the 6950 lost something like 3% . I wouldn't worry about it .

I'm just telling the OP how to get the best out of this board . The first two PCI-E x16 slots are controlled by the CPU while the third PCI-E x16 slot and the PCI-E x1 slots are controlled by the Z77, this is how the Sabertooth is setup.

 

[CrazyArsedMonky]

On your board stick the 670 in the top PCI-E x16 slot.

The third PCI-E x16 slot is controlled by the Z77 chipset, and runs in x4 mode (unless you plug in anything in any of the x1 slots). So you won't lose any of the x16 lanes to the GPU when you plug in a soundcard to the lowest x16 slot.

Excellent, thanks for the advice all

I might try the build without the soundcard then add it after for a comparison. If i do i will post my results here for the community!

P.S. Where do you guys learn your stuff? Are you in the business? Any recommended reading etc?

 

[Orcvader]

Excellent, thanks for the advice all

I might try the build without the soundcard then add it after for a comparison. If i do i will post my results here for the community!

You won't get any difference since the GPU will still have all x16 lanes .

 

[CrazyArsedMonky]

Doh, sorry you did say the first two were CPU controlled and the third was Z77 controlled /o\

I might whack it in the second slot, just to make my previous faux pas legitimate

 

[Orcvader]

Doh, sorry you did say the first two were CPU controlled and the third was Z77 controlled /o\

I might whack it in the second slot, just to make my previous faux pas legitimate

Bwahaha, fair enough . Guess you win there .

 

[OpenToSuggestions]

I'm just telling the OP how to get the best out of this board . The first two PCI-E x16 slots are controlled by the CPU while the third PCI-E x16 slot and the PCI-E x1 slots are controlled by the Z77, this is how the Sabertooth is setup.

I don't know much about the newer PCs I am afraid.
My late 2009 i5 rig just doesn't need upgrading .