Crossfire worse than single card for muliple games

techmaniac

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So I've recently purchased two Sapphire Toxic 6850 cards and installed. Removed all old Nvidia drivers. Games in xfire run choppy and worse than when crossfire is disabled.

System is vista x64 Ultimate
8gb ram
q9550
P35 chipset on Gigabyte mobo

Games that are crappy:

Borderlands
ETQW
Shattered Horizon

haven't tried others yet, but these are two are clear examples of crossfire being the problem.

 
Solution
I believe with that chipset you may be using...
PCI X16 (Full bandwidth)
and a
PCI X4 as your second slot (It's the same physical size as the X16 but doesn't run at the X16 speed just X4)

I would know for sure if I knew what your motherboard model was.

This is what it seems to say on the Gigabyte website for the majority of the P35 motherboards.

"1. 2 x PCI Express x16 slots (The PCIE_16_1 slot supports x16; the PCIE_16_2 supports x4.)"

They are trying to explain (not so well though) that it has two slots that are X16 in size but one only runs at X4 speed. This is somewhat comon. My motherboard has the same thing but since I know that second slot only runs at X4 speed I won't bother with Crossfire.

Depending on how the Crossfire...
1st, you should go to the driver site at AMD and download the crossfire profiles, listed just below the normal driver packs. This could fix your problem. Also, make sure you are playing in fullscreen, windowed mode does not support Crossfire/sli.

However, the dirty little truth is, crossfire/sli isn't always supported and sometimes have issues with games. Reviews and benchmark sites concentrate on benchmarks that are familiar so it's easier to compare, and they omit games which don't function correctly with crossfire/sli.

This leads a lot of people into believing CF/SLI is the best way to go. It's my opinion to always go for the single card solution first, unless there is no single card solution with the performance you need.

 

techmaniac

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Motherboard is Gigabyte GA-EP35-DS3P.

I did install one card (primary) and ran for a couple of days before installing the second. So at least one of the cards is confirmed as working.

I installed the 10.12 drivers right off the bat, and hadn't uninstalled the nVidia drivers before putting the new card in. Don't know if that is a possible problem.

 
I believe with that chipset you may be using...
PCI X16 (Full bandwidth)
and a
PCI X4 as your second slot (It's the same physical size as the X16 but doesn't run at the X16 speed just X4)

I would know for sure if I knew what your motherboard model was.

This is what it seems to say on the Gigabyte website for the majority of the P35 motherboards.

"1. 2 x PCI Express x16 slots (The PCIE_16_1 slot supports x16; the PCIE_16_2 supports x4.)"

They are trying to explain (not so well though) that it has two slots that are X16 in size but one only runs at X4 speed. This is somewhat comon. My motherboard has the same thing but since I know that second slot only runs at X4 speed I won't bother with Crossfire.

Depending on how the Crossfire operates this would explain why it's slower in Crossfire mode. If you check Gigabytes website for your motherboard specs you can see if that is the issue. If it is, the only fix is a new motherboard with 2 PCI X16 slots (physical size) that run at the full X16 (connection speed OR at least X8 connection speed). But I believe with a couple of nice video cards like the ones you have, they may be expecting that you have dual X16 (speed) slots.

If you ask me having 2 PCI X16 (size) slots is pointless if they don't run at the X16 speed as well. I think it's a somewhat of a trick to play on people. On the other hand I will likely use that second PCI X16 (size) slot (the one that runs at X4 speed) because I want to add a card for USB 3.0 and SATA 6 someday. And it's for purposes like that they really have a second slot running at X4 (speed).

I know it's a little confusing and stupid but it is what it is...
 
Solution

g00fysmiley

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bystander i agree except in 2 instances

1. where you need to space outupgrades over time.

2. 2 cards in crossfire or sli can create a price-performance zone unatainable

in a single card 6850's at around 170 a pop so 340 a pair for 340 you cna get a single gtx 570 or for 20-30 bucks more a 6970 niether of which beats the crossfire setup...

that said i would still take a single powerful card that will work well in all instances over one that will only work in games that will support xfire/sli ... i had to go sli gts 450's but i needed a card when my 8500gt bit the farm so i could only spend a limited budget and that made me use my own option 1... pickign up the second gts 450 tonight though from ups :D

started typing that before darklord posed and before OP posted mobo... yea 2nd pci = x4 at least for xfire or sli you want x8 on both , still could be drivers crippling them some, so follwo other advised btu you will have a baottleneck at that pci-e 16 x4
 

wiinippongamer

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facepalm-epic.jpg


"I installed the 10.12 drivers right off the bat, and hadn't uninstalled the nVidia drivers before putting the new card in. Don't know if that is a possible problem."

AND THERE'S THE 100% CONFIRMED CAUSE OF ALL YOUR PROBLEMS!

Unninstall the current ati drivers then reboot and put the old nvidia card back in (take the 6850's out first!) and uninstall the nvidia drivers you had, then reboot again then do as I said with driver sweeper UNDER SAFE MODE, reboot again this time with the 6850's back in and now install the newest ati drivers.
 

techmaniac

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Ahhhhhh, I see that now. It's not so much the drivers as the x4 on the second PCIe channel. What a load of @($!*#!!

At this point then, I'm inclined to return BOTH cards and purchase something bigger. It's not that a single 6850 won't perform. It does. I was hoping to add a third U2410 in the new year and have a sweet tri-monitor setup working.

Sigh.
 


Your #1 doesn't contradict me at all. You buy a single powerful card. You later add a 2nd, as an upgrade. Starting out with Crossfire/SLI is what I disagree with.

As far as your #2. The problem with those 6850's is they often don't out perform a single 6970. More often than not they do, but when they don't it's a large drop in the wrong direction.
 


That resolution, for gaming purposes, will likely take two 6970's for good performance. That's an extremely high resolution.
 

techmaniac

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So basically, if I'm looking to add that third monitor I might as well just build a whole new rig. Otherwise I see a bottleneck in other places should I just keep changing a few parts to meet this end.

Thanks for the contributions people.
 

Dokioto

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I'm wondering if I can also obtain some help in this thread.. I was about to make one of my own yet this was at the top sooo-

I have crossfire 5770's and my system specs are as fallowed-

Processor:
AMD 2.6 Quad Core 9950 (Black edition running at 3.0 Ghz)
Memory:
OCZ High Performance DDR2 PC2 8500 (4 GB)
Hard Drive:
Western Digital 500GB
Video Card:
CrossFire XFX 5770s
Monitor:
19.5" Samsung
Sound Card:
Onboard.
Operating System:
Windows 7 Ultimate 64 Bit
Motherboard:
Biostar TA790GX 128M
Power Supply:
NZXT PP-600

My motherboard doesn't have the 4x bull as techmaniac's did so I am stumped.

I have the latest profiles and drivers yet MW2, Black Ops, F1 2010, iracing are all getting better frame rates with crossfire disabled then enabled.

Help? I have been running one 5770 for some time, and decided i need a bit of performance boost but it hasn't helped at all :(
 


It's not just 3 monitors, but 3 high resolution monitors.

A single 6970 runs 1 1920x1200 monitor well, but once you triple that, you will have to turn the settings down quite a bit.
 

techmaniac

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Yes, but what about a 5970 running three of these puppys? Since it's technically two GPUS on one card.