SI3132 SATA2 PCI-E Controller Card Question

[grdh20]

Anyone hazard a guess as to whether a Silicon Image 3132 SATA2-300 PCI-Express controller card would be any faster than the on board (DFI NF4) Nvidia SATA2 controller for a Hitachi SATA2 drive?

[defakto]

It will have more bandwidth available to it if the onboard is attached to the pci-bus.

[grdh20]

so more than the PCI EXpress slot?

[feigned]

It's not going to matter what your upper limit of bandwidth is. 150 vs. 300 on a disk that can't possibly push out that many MB/sec...now using multiple disks reading and writing from the controller at the same time would be a slightly different story.

TCQ or NCQ or whatever it's called should be the only reason to use an SATA2 controller card.

[defakto]

oops, i typoed my answer


Typically pci-e will have more available bandwidth than std pci because of the point to point design.

Example, pci(all pci slots on a mobo normally) bandwidth is roughly 132MB/s max, slightly less due to error checking and what not. Say you have one harddrive that can do 50MB/s (most newer drives can put that out easy) So if you have 4 drives on the controller you can, in theory push out 200MB/s from the controller onto the pci bus. PCIe 2x slots have roughly 1000MB/s in bandwidth which can handle alot more than 4 drives without an issue. THe pci(std) issues become even more pronouced as you go above 4 drives.

Now that controller only has 2 devices(but sata2 supports port multiplexors) on it, so it won't be as much an issue if it was std pci. Don't forget though, you share that bandwidth with sounds cards, typically, usb and others also. It still can't hurt to go pci-e with that.

It's not going to matter what your upper limit of bandwidth is. 150 vs. 300 on a disk that can't possibly push out that many MB/sec...now using multiple disks reading and writing from the controller at the same time would be a slightly different story.

That's only true if you're dealing with a single drive on a single channel. Each drive will never max out the channel it's on. The more you put on teh controller though, the more it will tax the host interface. Not to mention that with sata2 you can add port multiplexors and quickly add drives to a sata channel and hit that 300 MB/s transfer rate and really overwelm what ever interface you're on.

[feigned]

oops, i typoed my answer


Typically pci-e will have more available bandwidth than std pci because of the point to point design.

Example, pci(all pci slots on a mobo normally) bandwidth is roughly 132MB/s max, slightly less due to error checking and what not. Say you have one harddrive that can do 50MB/s (most newer drives can put that out easy) So if you have 4 drives on the controller you can, in theory push out 200MB/s from the controller onto the pci bus. PCIe 2x slots have roughly 1000MB/s in bandwidth which can handle alot more than 4 drives without an issue. THe pci(std) issues become even more pronouced as you go above 4 drives.

Now that controller only has 2 devices(but sata2 supports port multiplexors) on it, so it won't be as much an issue if it was std pci. Don't forget though, you share that bandwidth with sounds cards, typically, usb and others also. It still can't hurt to go pci-e with that.



That's only true if you're dealing with a single drive on a single channel. Each drive will never max out the channel it's on. The more you put on teh controller though, the more it will tax the host interface. Not to mention that with sata2 you can add port multiplexors and quickly add drives to a sata channel and hit that 300 MB/s transfer rate and really overwelm what ever interface you're on.
Excellent info, not debating that because it is 100% true.

Just that the O.P. said "a" drive, not plural. One way or the other isn't going to make a whole lot of difference.

[grdh20]

Some quick HDtach 3.0 tests show that on a Tk7250 that the nvidia "on-board" SATA2-300 controller has about half the random access time of the Sil3132 card and wee bit better average read and burst, but the nvdia has 4% cpu and the card has 2%. Anyway, sticking with Nvidia's onboard. This was tested in the PCIE 4x slot.

[drizzt81]

can i ask where you got that PCIe SATA controller from and for how much?

[unhappy_mage]

PCIe 2x slots have roughly 1000MB/s in bandwidth
One pciE lane is 2.5gbps, with 8/10b coding. That means effectively 2 gbps. This is "only" 250 MB/s. Therefore, a x4 slot has a gigabyte per second of bandwidth, an x16 is 4gB/s, etc.

Just to nitpick ;) The rest of the post I agree with.

http://www.hardfolding.com/ftag1.php/mem/153.png (http://www.hardfolding.com?go=38&id=153)