- Joined
- May 9, 2011
- Messages
- 133
- Motherboard
- GA-Z68X-UD4-B3 BIOS:F10
- CPU
- Intel Core i5-2500K @ 4.8GHz
- Graphics
- XFX Radeon HD 6870 Dual Fan Edition
- Mac
- Classic Mac
- Mobile Phone
ok,
so i have a gigabyte GA-Z68X-UD4(as stated in the signature), and its a dual boot with windows 7 and mac os x lion 10.7.2, i also have a XFX 687A-ZDFC AMD Radeon HD 6870 graphics card currently installed in the top pcie slot. when i open up GPU-Z, it shows that the video card supports pcie 16x at v2.0, but it's currently running at pcie 8x at v2.0. it's really weird because i dont have anything plugged into the second pcie 16x slot, so i went to gigabyte's website to check this.
1 x PCI Express x16 slot, running at x16 (PCIEX16)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
1 x PCI Express x16 slot, running at x8 (PCIEX8) * The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.
so apparently, if i only have 1 pcie card(my video card) in the top pcie express 16x slot, then it should opperate at 16x, but GPU-Z says it's at 8x... is there anyway to disable the second pcie slot so that i run at 16x?
(my init display first in bios is set to pcie 16x)
i've attached a screenshot of GPU-Z
EDIT: ok, so apparantly CPU-Z says the same thing too!
i've also attached a screenshot of CPU-Z
EDIT 2: ok, so I went into Lion, and apparantly system profiler tells me the same thing
i've also attached a screenshot of system profiler
SOLVED: the problem was with the BCLK frequency, when it is disabled and at stock, it is 100MHz in the BIOS, but it actually runs at 99.70 MHz, and apparently, PCIe x16 requires BCLK to run at 100MHz at all times, so I went into the BIOS, and changed the BCLK control to Enabled and set it to 1003 instead of 1000, giving me a stable 100.1 MHz in both OS and I now have PCIe x16 speed!!!
so i have a gigabyte GA-Z68X-UD4(as stated in the signature), and its a dual boot with windows 7 and mac os x lion 10.7.2, i also have a XFX 687A-ZDFC AMD Radeon HD 6870 graphics card currently installed in the top pcie slot. when i open up GPU-Z, it shows that the video card supports pcie 16x at v2.0, but it's currently running at pcie 8x at v2.0. it's really weird because i dont have anything plugged into the second pcie 16x slot, so i went to gigabyte's website to check this.
1 x PCI Express x16 slot, running at x16 (PCIEX16)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
1 x PCI Express x16 slot, running at x8 (PCIEX8) * The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.
so apparently, if i only have 1 pcie card(my video card) in the top pcie express 16x slot, then it should opperate at 16x, but GPU-Z says it's at 8x... is there anyway to disable the second pcie slot so that i run at 16x?
(my init display first in bios is set to pcie 16x)
i've attached a screenshot of GPU-Z
EDIT: ok, so apparantly CPU-Z says the same thing too!
i've also attached a screenshot of CPU-Z
EDIT 2: ok, so I went into Lion, and apparantly system profiler tells me the same thing
i've also attached a screenshot of system profiler
SOLVED: the problem was with the BCLK frequency, when it is disabled and at stock, it is 100MHz in the BIOS, but it actually runs at 99.70 MHz, and apparently, PCIe x16 requires BCLK to run at 100MHz at all times, so I went into the BIOS, and changed the BCLK control to Enabled and set it to 1003 instead of 1000, giving me a stable 100.1 MHz in both OS and I now have PCIe x16 speed!!!