Overclock.net › Forums › Graphics Cards › Graphics Cards - General › Forcing x4 mode for testing.
New Posts  All Forums:Forum Nav:

Forcing x4 mode for testing.

post #1 of 11
Thread Starter 
Before you start flaming that this is stupid and ask why I would do it read.

So I want to crossfire my 5770's in my next build. but the motherboard I and looking at will run them in x16/x4 mode. I have no problem picking another board as long as it matches this PCI configuration and runs in x16/x8 or x8/x8.


I want the slots this way because I'm stuffing this board into a Lian Li pc-v354 want to crossfire with a tv tuner in between the the cards for air flow and I don't want to use usb/external boxes.

So a long story short. Are there any tuts for taping/covering the extra pci-e connectors to force it to run in 4x mode so I can see if I will suffer any performance. I want to do this to gather my own data. Yes I have seen the 5870 in 4x mode gets 95% pictures and charts and the whole nine yards. Also my board doesn't have an option to "run pcie in x mode"

I plan to post results and pictures of my findings when I'm done. Thanks in advance for the help.
post #2 of 11
Yes, you can use adhesive tape to insulate, just as what TechPowerUp has done in their tests:

Links:
http://www.techpowerup.com/reviews/A...press_Scaling/

http://www.techpowerup.com/reviews/N...press_Scaling/

And here is the lane layout of the connector:
http://www.tomshardware.com/reviews/....0,1915-4.html

Good luck and post your result when done.
post #3 of 11
Thread Starter 
I knew Someone had done it with a ?480? I think. Thanks for the links. I will as soon as I manage to tape off one of my cards.
post #4 of 11
Thread Starter 
so I have run into a problem. I can't get it to boot. I'm using masking tape to cover the extra connectors. I have looked at a few pictures on line to count the pins on a few different x4 cards. I have come to find that there are 21 pins on a 4x card. So I have masked off 23- the end. I'm not getting a boot. But I am gonna try reseting bios and and trying again.

Could a few one you great people on the forum please count/link the amount of pins on an x4 card?
post #5 of 11
Quote:
Originally Posted by animal0307 View Post
so I have run into a problem. I can't get it to boot. I'm using masking tape to cover the extra connectors. I have looked at a few pictures on line to count the pins on a few different x4 cards. I have come to find that there are 21 pins on a 4x card. So I have masked off 23- the end. I'm not getting a boot. But I am gonna try reseting bios and and trying again.

Could a few one you great people on the forum please count/link the amount of pins on an x4 card?
I count 32 from this pic:
http://www.tomshardware.com/gallery/...15-1-jpg-.html

And, here says 32 too:
http://en.wikipedia.org/wiki/PCI_Express
post #6 of 11
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
I5 2500K AsRock extreme4 p67 GTX 470 SLI 8gb Gskill 
Hard DriveOSMonitorKeyboard
Crucial 128gb,WD black 1tb, Seagate 500gb windows 7 64 bit Enterprise U2311H Razor 
PowerCaseAudioAudio
Antec HCP 1200 Corsair 800D xonar DX M-Audio BX5a 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
I5 2500K AsRock extreme4 p67 GTX 470 SLI 8gb Gskill 
Hard DriveOSMonitorKeyboard
Crucial 128gb,WD black 1tb, Seagate 500gb windows 7 64 bit Enterprise U2311H Razor 
PowerCaseAudioAudio
Antec HCP 1200 Corsair 800D xonar DX M-Audio BX5a 
  hide details  
Reply
post #7 of 11
Thread Starter 
Ok so it is 32 of you count from the very first pin. I wasn't counting the first tab cause it was the same for all types. Well now I gotta try something. maybe thinner tape will do the trip. The masking tape is rather thick.
post #8 of 11
Quote:
Originally Posted by animal0307 View Post
Ok so it is 32 of you count from the very first pin. I wasn't counting the first tab cause it was the same for all types. Well now I gotta try something. maybe thinner tape will do the trip. The masking tape is rather thick.
Yes, 11 + 21 = 32 total (counting from the 1st, or 21 counting from the 1st key notch). See pic below for PCIe x4.

And, masking tape is perhaps a little too thick. Try Scotch tape or equivalent.
post #9 of 11
Thread Starter 
OK so now I'm think my motherboard can't do it cause its a pcie v1.0 slot and not a 2.0. Does that make a difference? PCIe cards are backwards and forwards compatible with all slots if they fit. But does a pcie 1.0 slot have a x4 mode?
post #10 of 11
Quote:
Originally Posted by animal0307 View Post
OK so now I'm think my motherboard can't do it cause its a pcie v1.0 slot and not a 2.0. Does that make a difference? PCIe cards are backwards and forwards compatible with all slots if they fit. But does a pcie 1.0 slot have a x4 mode?
Simply put, the major difference between PCIe 1.x and 2.0 is that the max transfer bandwidth of the latter is doube that of the former. So, putting a PCIe 2.0 x16 card into a 1.x x16 slot will make it work like a x8 card. And, tests have shown that the max performance loss is only 1% at 1280x1024 (native resolution of your Rosewill R912E).

As to your 2nd question, PCIe 1.x has x1, x4, x8 and x16 modes/slots just like PCIe 2.0.
PCIe 1.x x4 has the same bandwidth cap as a PCIe 2.0 x2. However, there is no x2 mode and so you cannot cover up portion of the lanes of a PCIe 2.0 x16 card to make it work like a PCIe 2.0 x2 mode in order to simulate a PCIe 1.x x4.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Graphics Cards - General
Overclock.net › Forums › Graphics Cards › Graphics Cards - General › Forcing x4 mode for testing.