Crossfire 6870's hardly run well at all, laggy

My custom built desktop runs super fast, except when it comes to gaming. For some reason, my graphics card doesn't run games very well. I have a Sapphire 6870, actually 2 (crossfire) and when I play games like battlefield 3 I only get about 27-45 frames per second on ultra graphics, and with Skyrim I only get around 27-39 frames per second on ultra. I read online that my specs should be more than enough to handle it. Running only one card, it runs well but doesn't get as high of a performance as crossfire. Few things you should know first though:
-FPS dips randomly, lags occasionally on simple games like Black ops (stays at 60 FPS then drops all of a sudden to 40 while lagging for about 5 seconds, then shoots back up to 60)
-When playing skyrim, even when it is installed on my solid state, it lags when I do a quick turn (look around fast)
-Both are the same exact cards and model number, cross fire is shown to be enabled in both CCC and GPU-Z
-When monitoring my GPU usage on my second graphics card in GPU-Z, it shows that there is 0% activity where my primary video card has about 7% idle, and my secondary stays 0% even after intense gaming
-Both graphics cards are plugged in 16X PCI-Express ports but only one of them is using 16X while the other is using 4X (no idea why, bios only gives me the option to enable 4X)

I'm not sure where I went wrong with my crossfire, I have already uninstalled and reinstalled the drivers multiple times, done a driver sweeper and both CCC and GPU-Z show they are working properly, except for the fact in GPU-Z it shows 0% activity. Any troubleshooting tips or experiences with fixes would be extremely helpful.

Below are my computer specs:

Desktop Specs:

*CROSS FIRE* 2X Crossfire SAPPHIRE 100314-3L Radeon HD 6870 1GB 256-bit GDDR5

Cooler Master HAF 922 RC-922M-KKN1-GP Mid TowerCase

DiabloTek PSUL775 UL Series ATX Power Supply - 775W

Corsair CMFSSD-64D1/RF2 Extreme Series X64 2.5" Solid State Drive - 64GB, SATA II 3Gb/s

Seagate 1TB Serial ATA HD 7200/32MB/SATA-6G

Asus M4A88T-V EVO USB3 Motherboard - AMD 880G, Socket AM3, ATX, DDR3, RAID, SATA, VGA, DVI, HDMI, USB 3.0

AMD HDT90ZFBGRBOX Phenom II 1090T Black Edition Six Core Processor 3.20GHz

2X (8gb) Kingston KHX1600C9D3B1/4G Desktop Memory Module - 4GB, PC3-12800, DDR3-1600MHz

Lite-On IHAS124-04 Internal DVD Writer - DVD+R 24X, DVD-R 24X, DVD+RW 8X, DVD-RW 6X, DVD+R DL 8X, SATA
8 answers Last reply
More about crossfire 6870 laggy
  1. Whilst im playing battlefield 3 I got some low level lagg spikes on ultra as well. But that was with installed in my HHD i moved it to my SSD and it runs perfect and also bumped up my performance of my graphics card and added a second exhaust fan to my case. maybe try cooling it some more.

    Operating System
    MS Windows 7 Ultimate 64-bit
    Intel Core i7 2600K @ 3.40GHz 50 °C
    Sandy Bridge 32nm Technology
    8.00 GB Dual-Channel DDR3 @ 665MHz (9-9-9-24)
    Gigabyte Technology Co., Ltd. Z68A-D3-B3 (Socket 1155) 41 °C
    E2441 (1920x1080@60Hz)
    AMD Radeon HD 6900 Series (ATI AIB) 39 °C
    Hard Drives
    1954GB Seagate ST2000DL003-9VT166 ATA Device HDD (SATA) 32 °C
    112GB OCZ-VERTEX2 3.5 ATA Device SSD (SATA) 30 °C
    Optical Drives
    TSSTcorp CDDVDW SH-222AB ATA Device
    Realtek High Definition Audio
  2. Yea cooling it doesn't seem to be the problem, I have a coolermaster case which has excellent cooling, my graphics card never run higher than 60 degrees except when benchmarking. And the strange thing is also, is that when I benchmark with Furrmark, it runs up to about 65 degrees but only uses about 70% of each graphics card, which I thought was super whack.
  3. Skyrim doesn't support CF at this time. Not sure about BF3.
  4. 4745454b said:
    Skyrim doesn't support CF at this time. Not sure about BF3.

    Haha yeah i actually JUST read that on a forum on here. *faceplam* but aside from that the performance is underwhelming. :(
  5. yea having such a good system it should all run smoothly have you tried updating your AMD drivers?
  6. xlokwinterx said:
    yea having such a good system it should all run smoothly have you tried updating your AMD drivers?

    I actually haven't to be honest with you. The graphics card driver is fully updated but perhaps my CPU driver is outdated. When I get off of work I'll be sure to double check but I'm almost positive it is.
  7. The thing is if you are testing with programs that don't support CF, you'll get that "underwhelming" experience. In those cases you'll only be using one of the 6870s, and if it can't cut it in that game then you'll have all kinds of issues. Such is the hassle of multicard setups.
  8. 6870's CF will basically emphasize a rendering bottleneck all that much more due to its architectural performance and the fact that dual GPU setups is still detected as a pair of individual GPUs rather than combining both into one massive rendering engine.
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