Annoying problem!! GTX 580 4 way SLI capped @ 48 FPS - HELP NEEDED

[Tukmolly]

GTX 580 3gb quad SLI + Asus Rampage IV Extreme - LOCKED @ 48FPS

Hi there,
I recently added a 4th water cooled GTX 580 3gb to my system. I'm currently running
an X-79 mobo, the ASUS Rampage IV Extreme paired with an Intel Core i7 3930 OC'd to 5.1ghz. My RAM is a
set of 16gb Mushkin Redline series @ 2133mhz. My PSU is a Silverstone 1500watt Strider series..and of course
four EVGA GTX 580 3gb Hydrocopper 2 in quad SLI. My OS is Win 7 64bit. I have 3 Samsung 305t in surround,
with a total resolution of 8020 x 1600. I mainly use my PC for surround gaming. My issue began when I added a
4th GTX 580 in the hopes that going from tri to quad SLI would help me gain some more badly needed FPS boost
in games like BF3,Batman Arkham City, BFBC2, Metro 2033, Mafia 2, Crysis 2, Dirt 2, Dirt 3, Rage, Max Payne 3 & other
modern DX10, and Dx11 games. I updated my video driver to the latest 301.42 of course as well as the latest mobo
BIOS from the ASUS site (version 1404). I correctly configured my surround as I've extensive experience in
surround for well over two years now.When I was running triple SLI, my games which weren't that demanding were
hitting my VSYNC'd rate of 60 FPS. More so if VSYNC is OFF. Some games like BF3 and other newer DX 11 titles
of course would only hit mid to high 40's at my resolution. So I thought a 4th 580 might help. Alas!! I was wrong!
Since I had my 4th videocard,my FPS on Vsync ON has been locked to 48 FPS!!, Even previously lighter games which didn't
have issues before, were ALL capped at 48 FPS. Overall, I felt my games are performing less and a bit more
stuttery. My PCIe lanes are operating @ 16x 8x 8x 8x as verified by both my BIOS and GPU-Z. Even when I turn OFF
Vsync, my frames dont get past 50 FPS and the games feel rough and stutters. I'm at a loss here as I thought
the X-79 platform has somehow negated the CPU/ PCIe bandwidth bottlenecks seen in previous platforms.
My PCIe lanes of course are running at PCIe 2.0 given that the 500 series are GEN2 anyways. Have you guys encountered this
problem and if so, what have you done or researched to fix it? Is there a registry hack out there to ensure that my
four GPUs are fully utilized? Or am I missing crucial BIOS tweaks to aid in my PCIe bandwidth? Some DX11 titles such as BF3
only shows 40 to 65% GPU usage accross all 4 of them.Does quad SLI simply over saturate my 40 PCIe lanes, hence the cap?
Do you guys recommend that I dump my quad config and just go back to 3way SLI and or just wait for the
GK 110 cards? I'm skipping the 680s to maximize my investment with the 580s. Any ideas, tips or insights will be of
utmost value to me. Are there any tweaks in the BIOS I'm missing? CPU BCLK skew vs. PCIe lanes skew? HELP!!!!
Thanks to everyone.

[Myk_SilentShado]

Considering you are using PCIe 2.0 cards in 3.0 slots, your cards should be running at x4 across the board since PCIe 2.0 only supports 16 lanes.
And as a side note PCIe 3.0 has 32 lanes, not 40.

[DaemonCantor]

This has been addressed in lots of places where it's not worth going 4-way on ether nVidia or Crossfire because the games don't Scale Well with 4 cards as they do with 2 or even 3 and the best Scaling was at 2 cards.

[Tukmolly]

Myk SilentShadow

Thanks for your input my friend..I'd like to clarify a few things however, The X79 platform has 40 PCIe lanes.(2.0) That's why the RIVE mobo supports 4 way SLI running @ x16, x8, x8, x8. My previous X58 platform supported only 32. Now, checking with the mobo's built in PCIe simulator via BIOS confirms that whether I use PCI2 2.0 or 3.0, All my 4 GPUs are running @ x16,x8,x8,x8. This has been verified by GPU-z as well.The 40 lane PCIe bandwidth feature of the X79 platform is the very reason why I thought 4 way SLI is finally worth testing.