What are the performance differences between PCI-Express x16 and x4

Posted by Cestarian on Super User See other posts from Super User or by Cestarian
Published on 2014-06-10T08:11:46Z Indexed on 2014/06/10 9:28 UTC
Read the original article Hit count: 455

Filed under:

graphics-card

|

motherboard

|

pci-express

I have two PCI-Express 2.0 x16 slots on my motherboard, but one of them is actually just x4.

For passing through my graphics card to a virtual machine I need to use both slots simultaneously and unfortunately, the easiest way for me to achieve that is putting the stronger card in the x4 slot (secondary slot; I need the stronger card to be in the secondary slot, not the primary).

As such I am wondering what sort of noticable performance differences I can expect from using the x4 slot with a strong card as opposed to having it in the true x16 slot. Does it limit the performance so much that the strong card in the x4 slot will actually perform worse than the significantly weaker card in the x16 slot? (For spec comparison I am using a GTX-670 in the x4 slot and GTX-550-Ti in the x16 slot)

What implications does this have?

© Super User or respective owner

Related posts about graphics-card

Graphics card fan is loud (additional graphics card drivers cause problems)

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Okay this explanation is a bit longer ... but I start at the beginning: I've been using Windows 7 for a very long time, shortly after the release of v12.10 I installed Ubuntu via Windows installer. Everything worked fine but the fan of the graphics card. After a bit of research I found out, that… >>> More
asus smartdotctor "can not find graphics card information"

as seen on Super User - Search for 'Super User'
Hi, I am not sure that this is the place I can ask questions like this, but I'll give it a try. I have a Windows 7 64bit, new graphic card ASUS ENGTX260 MATRIX, installed latest graphics drivers nv19045_Win7Vista64 and ASUS Smart Doctor version 5.44. Unfortunately, after the required reboot when… >>> More
Graphics card not working but integrated graphics is working

as seen on Super User - Search for 'Super User'
I have a PCIe Geforce 6600 that I've been using in my PC for a couple years now without problems. Recently though I've not been using the PC and had it unplugged. When I when to use it again I accidentally plugged in the monitor to the VGA port for the integrated graphics instead of the 6600 card… >>> More
Gigabyte Onboard graphics card heating up and then crashing

as seen on Super User - Search for 'Super User'
5 minutes after I turn on my PC the onboard graphics card is usually over 80° celsius and then crashes (random colors on screen, only way to get out is to just plug out the pc). I haven't installed any new drivers or added/changed hardware recently Everything went fine until yesterday What should… >>> More
Graphics card initialisation problems when booting - requires a "double" boot

as seen on Super User - Search for 'Super User'
Problem Outline When booting from cold (and my machine is disconnected from main power when off, but leaving it connected doesn't help) the graphics card (single PCI-e card GeForce 460) will not initialise on the first boot, leaving me with the motherboards on-board graphics (which kick in automatically… >>> More

Related posts about motherboard

Motherboard Wiring

as seen on Super User - Search for 'Super User'
HI All, I bought a new case to put a motherboard in. Everything fits, I have done this before, but not in a long time! The case has wires for - Power SW - Reset SW - Power LED - HDD LED On the motherboard (ASUS M2NPV-VM) it is clearly labeled where these go, but I cannot remember where the black… >>> More
xfx 680i motherboard failure?

as seen on Super User - Search for 'Super User'
At some point last night we must have had a blip in our power, as the stove clock was blinking like it would had their been... a blip in the power. When I came into my office this morning, my desktop computer was powered down and would not turn on. Cracking the case, I can see a small blue blinking… >>> More
Current Motherboard Tech Overview

as seen on Super User - Search for 'Super User'
Welp, computer died. Time to get a new motherboard. I haven't been paying attention to the latest motherboard technology and associated models and chipsets. Can someone point me at an overview of what is currently available? I'm primarily interested in the Intel / nvidia side of things. >>> More
Processor with higher FSB than motherboard can support.

as seen on Super User - Search for 'Super User'
Hi all, Please redirect me if there is a similar question, but I have an ECS P4VXASD2+ (V5.0) motherboard, which supports a 533 MHz FSB. I want to put in a Pentium 4 3.2 GHz processor (Socket 478) with an FSB of 800 MHz. Would this be possible? Would the FSB of the processor just be limited to 533… >>> More
How to get Processor and Motherboard Id ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I use the code from http://www.rgagnon.com/javadetails/java-0580.html to get Motherboard Id, but the result is "null", <1 How can that be ? <2 Also I modified the code a bit to look like this to get processor Id : "Set objWMIService = GetObject(\"winmgmts:\\\\.\\root\\cimv2\")\n"+ … >>> More