Ok so I have a problem. I have a HAF 922 Case and I have 2 x8's, 1x16 and a x4 slot
Problem I'm having is one x8 slot is right under the x16 slot and I can't stick a card in there. The other x8 slot is all the way at the bottom and the power supply is blocking any card I want to put there. The only solution I have is to stick my second card into an x4 slot. Is that not worth it for a 2nd 6850 or is there a better case that would help solve this problem?
"The Bottom Line
The results are actually a bit shocking to us to be honest. We weren’t so surprised that in the previous evaluation x8/x8 did not cause any differences at 2560x1600 but did at 5760x1200. However, we thought certainly at x4/x4 PCIe 2.0 mode there would be some kind of a bottleneck at 2560x1600, but the results have proven otherwise. Even with all the data that GTX 480 SLI is pushing across the PCIe bus, x4/x4 is NOT a bottleneck in a single display setup at 2560x1600 with AA enabled. The only game to show us any difference was AvP, but it did not affect the gameplay experience. Therefore, if you are on an aging PCIe 1.X system at x8/x8 mode (equivalent to PCIe 2.0 x4/x4) on a single display fear not, you are not holding back the performance of GTX 480 SLI or we guess with any CrossFireX or SLI configuration." http://www.hardocp.com/article/2010/08/25/gtx_480_sli_p...
I believe that LE , in this case means - light edition.
The X58 chipset supports a total of 40 pci e lanes.
But the m/b manufacture still has to build in switching controllers which cost 'money' to enable various pci-e lanes for the physical slots they include on the board.
In this case they chose, electronics ,and a bios to support only 16x-8x
It could be worse, some make this scenario 8x-8x
They use this as a pricing positioning tool within their own board lineup.
edit: light edition specifications correspond with the micro-atx format which this board is.
Because of its size and intended usage, possibly HTPC cases , which are smaller. The overall intended 'usage' of this board is scaled down. That applies to overclocking prowess also.
The X58 SLI Motherboard from EVGA is designed for the win. Featuring EVGA VDroop control for maximum voltage stability while overclocking, Onboard Clear CMOS, Onboard power and reset buttons with built in power and hdd activity led indicators, EVGA E-LEET tuning utility which provides quick access to overclocking controls without going into BIOS, and onboard Debug LED's for current CPU temperature reading, your system will be able to handle the latest games, high definition digital video, and Windows Vista with aplomb. Additional features of the 141-BL-E757-TR include support for Intel Core I7 processors, Intel X58/ICH10R chipset, 6 DIMM Triple Channel DDR3 up to 1600MHz, Enthusiast Layout supporting 2-way SLI, 3-way SLI with PhysX, 6 SATA II 3 GB ports, Gigabyte ethernet port (10/100/1000), 8 channel audio (includes COAX and optical), 12 USB 2.0 ports (8 I/O, 4 External), 2 1394 external Firewire slots, and passive heatsink. Product comes with a 1 year warranty and a second year free if registered at www.evga.com within 30 days of purchase
The problem is not the lane count but the actual bandwidth that the cards receive between them and access to the cpu. You may be able to saturate this link but you won't be scaling as well as those who have 8x8 or better. The problem is the mirroring of data between both cards is that one is going to be slightly lagging behind the other so you will lose what you would have normally had in terms of gains so being highly conservative that you should expect 40-60% instead of 90%.
I was also considering a different case. Any case that would solve this problem that's not super expensive?
It depends on quality and taste, I ended up using an 11 year old rust bucket simply because it was easy to manage cabling and cooling plus it was free but for you try looking around I am sure that you might find something that isn't to bad that is cheap. You can try making some custom mounts for a spare case fan or two and keep your current case instead that will cool the cards.
I don't think you can just generalize from triple crossfire results to dual crossfire. Going in the opposite direction techpowerup did an article showing a x4 slot only limits an HD5870 by about 5% on it's own.