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Why is my 5870 running at 8x?

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  • Graphics Cards
  • Graphics
Last response: in Graphics & Displays
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April 25, 2010 11:44:46 AM

Hey

as the title states my XFX 5870 GFX card is running at 8x and i am not sure why... my motherboard has 2 x16 2.0 and it runs x8 x8 in SLI/Crossfire

i have an asrock M3A790GXH/USB3, GPU-z reports it running at 8x and in CCC in the hardware section it states that the max bus speed is 8x

my friend said that it might be because onboard crossfire might be enabled, how do i see if this is true?

also is there any hard is leaving it running at x8?

Kind Regards

Nytrus90

More about : 5870 running

a c 130 U Graphics card
April 25, 2010 11:54:33 AM

I have seen this before and it seems that on a 2.0 PCIE slot X8 is teh same as X16 on a PCIE 1 slot so it should be fine. I dont know why it does it but there you go, just computers being confusing again i guess.
What does GPU Z say your bandwidth is ? should be around 153.
If its reporting that correctly then i wouldnt worry.

Mactronix
April 25, 2010 12:29:37 PM

Hey

thanks for your reply my bandwidth states its at 115.2GB/s

guess i have a problem? lol

kind Regards

nytrus90
Related resources
April 25, 2010 1:21:34 PM

rl70 said:
The manufacturer homepage gives you information that the board only supports 8x/8x in double card usage and 16 in single card usage. So everything is at it should be. You can find it here: http://www.asrock.com/mb/overview.asp?Model=M3A790GXH/U....


But he is not using crossfire so it should be running at 16X.
April 25, 2010 1:27:12 PM

Oy vey, "my motherboard has 2 x16 2.0 and it runs x8 x8 in SLI/Crossfire " I thought this should tell me that his motherboard supports x16 x2 but it only runs in 8x/8x.
a b U Graphics card
April 25, 2010 2:28:28 PM

How many PCI-E lanes do you have? Are you using it in a slot that gives x16 speeds?

For example my board has 4 PCI-E x16 lanes. Only slot 1 and 3 has sufficient pins to run at actualy x16 speeds while the other two has only half the pins thus hardware limited to x8.
April 25, 2010 6:50:14 PM

Hey

sorry for the confusion, my mobo has 2 x16 2.0 lanes (blue) and 1 x4 lane (white)
both the lanes run at x16 2.0 BUT in crossfire/sli it runs X8. My GFX card is in the top lane. (1st PCI-E slot)

hope this helps

Kind Regards

Nytrus90
a c 130 U Graphics card
April 25, 2010 7:31:06 PM

Do youu have it in the correct slot ? some Mobo's will detect the second slot being used and just assume two cards are there and switch to X8.
Check the specs with something else as well CPU Z can get it wrong some times, Si Soft sandra Lite is quite good and is a free download that i use from time to time for a second opinion.

Mactronix
April 25, 2010 7:44:46 PM

Hey

Yes i have it in the correct slot, but still both lanes are x16 when not in crossfire/SLI.

also i have used CCC and that also states that its running at x8 also everest also states its running at X8

is there any harm bottle neck wise?

Kind Regards

Nytrus90
a b U Graphics card
April 25, 2010 7:58:54 PM

There will be some bottleneck. Anywhere from 0% to 10% depending on the resolution and game.
April 25, 2010 8:00:31 PM

dang.... anything i could try to sort this out?

Kind Regards

Nytrus90
a b U Graphics card
April 25, 2010 8:13:26 PM

Try flashing your boards BIOS?

Make sure the the pins in the graphics card is clean. Since cards would automatically run at 1x,4x or 8x if the pins are covered.
April 25, 2010 8:14:04 PM

hmmmm id rather have a 10% bottle neck then a bricked mobo lol

any leads on my friends comment on how the onboard might be in crossfire with my gfx card?

anyway to check?

Kind Regards

Nytrus90
April 25, 2010 8:17:43 PM

ok GPU-z states that crossfire is disabled.

hmmmmm
a c 180 U Graphics card
April 25, 2010 8:31:13 PM

TECH ANSWER:

I looked at your manual. There is a single Crossfire switch on the motherboard; it goes one way for single card in x16 mode or the other way for Crossfire 2x8 mode.

A PCIe x8 (v2.0) slot is sufficient for an HD5870. You will NOT see a difference between x16 and x8 for an HD5870. They tested this specifically to see if the 1156 boards would be limited. They tested with an HD5870 (non-overclocked) in x16 mode then blocked part of the x16 slot so it provided only x8 bandwidth. Less than 1% difference was observed.

You can add a second HD5870 in the future if you wish with no bandwidth issues. Do NOT mess around with three cards. Two HD5870's will max out the bandwidth and likely your CPU as well for many games.

CPU overclocking:
Do NOT overclock unless you will see a benefit. For example, open the Task Manager (CTRL-ALT-DEL) and set it to "Hide when minimized" and "Update speed->LOW." RUN the TM in the background during a game for at least 5 minutes. Observe the CPU level (show all threads). If no thread/core reaches 100% then overclocking is not needed. If a single thread reaches 100% it's harder to say.

VSync:
Don't forget to run VSync in games. This forces the game to run at your screen refresh rate (usually 60Hz). For example, an older game I have ran at 300FPS without VSync and my CPU was at 100%. Enabling VSync ran the game at 60FPS and my CPU was at 25%. VSync also eliminates "tearing" of the screen (google it). Generating frames that your screen can't display just uses power and increases fan noise.

Optimizing:
There are lots of tips. In general, it's better to have higher frame rates (up to the monitor refresh rate) than to have better graphics but slow frame rates and stuttering. Some effects like Shadows and AA can have a huge performance hit with minimal benefit so play around.
April 25, 2010 8:34:45 PM

Amazing, Thank you very much :D 
a c 130 U Graphics card
April 25, 2010 8:46:14 PM

Yes you shouldn't get a performance hit even if its running at X4 it would be negligible, we need to get to the bottom of why your card is running at the same bandwidth as a 4870.
It really seems to me that a bios setting being wrong is the most likley cause.

Mactronix
a c 130 U Graphics card
April 25, 2010 8:53:45 PM

Ok so i just checked out the MOBO and it has a card that physically switches the slots to 1x16 or 2x8. what is your card set to ?
does it read 1X16 0r does it read 2x8 when you look at it ?

Mactronix
April 25, 2010 8:55:31 PM

hey

its on the 1x16.

Kind Regards

Nytrus90
May 2, 2010 5:18:06 AM

It doesn't matter running the cards in 8x. They do not use all the bandwith. your performance will be the same 16x or 8x.
May 3, 2010 2:24:44 AM

SOLVED:

ok guys ive solved the issue.

HOW DID I DO IT?

well basically i took the card out and blew on the PCI-e slot and the GFX card gold fingers, then stuck it bk in and HEY PRESSTO!

thank you for all your input on this matter.

Kind Regards

Nytrus90
a c 273 U Graphics card
May 3, 2010 5:54:30 AM

nytrus90 said:
SOLVED:

ok guys ive solved the issue.

HOW DID I DO IT?

well basically i took the card out and blew on the PCI-e slot and the GFX card gold fingers, then stuck it bk in and HEY PRESSTO!

thank you for all your input on this matter.

Kind Regards

Nytrus90

But has there been any noticable difference in performance?
May 3, 2010 4:56:14 PM

erm..... yeah.... for what it might be minor but when running the 1st intro bit to the unigen benchmark it run at 18 fps @x8 and 20 fps on X16

Kind Regards

Nytrus90
a c 273 U Graphics card
May 3, 2010 4:59:49 PM

nytrus90 said:
erm..... yeah.... for what it might be minor but when running the 1st intro bit to the unigen benchmark it run at 18 fps @x8 and 20 fps on X16

Kind Regards

Nytrus90

So x8 is not the same as x16 then!
!