GA-P55-UD3 -- Turbo SATA3/USB 3.0 BIOS Setting Question

[mdheller]

So I have a GA-P55-UD3 mobo with a Corsair Force 3 120GB SSD connected to the Marvell SATA3 port serving as the boot drive. I also have an Nvidia GForce GTX 460-based video card plugged into the PCIEX16 slot. I'm running Win 7 64-bit, and things seem stable. However, I'm not getting quite as much speed out of the Corsair SSD as I was expecting. Here's the HDTune results:



The read speeds are fine, but the write speeds seem to be getting throttled at around 225 MB/s. Now this is more than twice the write speed of any other HD I have, so if this is what I get, I'm fine with it. I know that the Marvell controller sucks, but the SSD performs much better on the Marvell than on the Intel iTE IT8213 SATA2 controller.

My question is around the "Turbo SATA3/USB 3.0" setting in BIOS. Apparently this determines whether either the SATA3 or USB 3.0 controller is set to PCIe Gen 2 speed. It's currently set to "Auto". However I'm wondering if I set it to "enabled" for SATA3 would I get the full write speed from the drive? But if I do, will I lose bandwidth for my video card? The manual says "when only one graphics card is installed on the PCIEX16 slot, it will operate at up to x8 mode if either one of the two controllers is set to PCIe Gen 2." So if I enable turbo for SATA3, my video card speed will be cut in half? Am I reading this right?

Any thoughts would be much appreciated!

[wazza300]

Re: GA-P55-UD3 -- Turbo SATA3/USB 3.0 BIOS Setting Question

Yes that's right because the p55 chipset robs bandwidth from the pci-e reducing it to 8x speed when sata3 usb3 are used,don't worry though 8x pci-e is plenty fast enough unless your using super high resolution or multiple monitors

[mdheller]

Re: GA-P55-UD3 -- Turbo SATA3/USB 3.0 BIOS Setting Question

Well, I tried setting the Turbo SATA3 to enabled and saw no improvement in my Corsair Force 3 write speed. So I changed it back to Auto.

I guess this is the speed I'll have to live with (which isn't bad, just not as good as it could be). I've heard that the Marvell 9128 is limited to around 400 MB/s read and 250 MB/s write no matter what you do. Maybe that's true. Though how that equates to SATA3 I don't know. I guess the fact that it's faster than SATA2 means it must be SATA3. But that doesn't mean it's as fast as the SATA3 spec allows.

[wazza300]

Re: GA-P55-UD3 -- Turbo SATA3/USB 3.0 BIOS Setting Question

Only the Intel sata3 ports found on sandybridge will give you full ssd spec read/write figures,I havnt seen any Intel sata3 pci/pci-e add in controller cards either as this would be a good work around

[mdheller]

Re: GA-P55-UD3 -- Turbo SATA3/USB 3.0 BIOS Setting Question

Yeah, I thought about an add-in controller. But I really don't want to spend any more money on this right now. What I have is not all it could be, but at the moment anyway, it seems to work OK. I'll probably stick with it for now. Maybe down the road I'll get an add-in controller (when those 400 MB/s read rates start to seem slow....) ;)