MrJP wrote:In theory a 1x PCIe connection will be a bottleneck for a 6Gb/s SATA connection, though as you've found with your X58, in the real world this probably won't be a noticeable problem (except in some extreme benchmarks) as long as you don't try to run multiple SSDs off a single controller chip. I wasn't saying you should necessarily avoid this situation, just that you shouldn't get conned into paying more for a card with a 4x PCIe connector for single drive performance reasons when in reality it has exactly the same bottleneck as the cheaper 1x PCIe cards. There's still a possible benefit there with the 4x card if you're going to run two SSDs, as long as you make sure that the ports you use are using separate controller chips.
kumori wrote:I was looking into doing this same thing on my X58 board. It turns out that these PCI-e to SATA III adapters do not support TRIM and are only slightly faster than a SATA II port. In general, these cards do not provide actual SATA III speeds.
You might have seen it before, but this is a link to a similar discussion that happened when SATA III was just becoming available.
canoli wrote:Sh-- thanks for pointing that out. No way I'm wasting money on a PCIe x1 card. The Koutec (whoever they are) doesn't specify and the reviews aren't great all in all. Lot of compatibility issues it seems.
canoli wrote:I took it for granted these cards would all be PCIe x16 or x8 by now. Do I need to spend $$ and buy a real RAID card to get the top PCIe speeds?
MrJP wrote:Be aware that many of these cheap PCIe x4 cards actually have multiple PCIe x1 SATA controllers connected via a bridge chip and therefore are capped at a maximum PCIe x1 bandwidth on any individual SATA port.
It can be hard to work this out from the manufacturer specifications, but if you look at the Startech details here you can see that it lists the controller as the Marvell 88SE9128 with bridge chip PEX8604. If you Google the controller name, you can find a datasheet here which shows that the chipset PCIe link is just x1 width.
canoli wrote:Were you saying the PEX8604 - what you termed the "bridge chip" - is that the concern? I can't find anything on that chip unfortunately.
Bauxite wrote:Just noticed this, no excuse to put up with any of those cheapo cards right now:
http://www.servethehome.com/ibm-servera ... 5-dollars/
http://www.ebay.com/itm/IBM-ServeRaid-M ... 1005070363?
Bracket optional, might be able to make your own or reuse another cards as they tend to be gouged a bit on ebay. ($10+ and shipping for 0.50c part = sigh)
Two cables per card from here, you want the "Mini SAS 36pin (SFF-8087) Male to SATA 7pin Female Cables - Forward Breakout":
http://www.monoprice.com/products/subde ... p_id=10254
(forward = SAS HBA to SATA drives, reverse = from SATA controller ports to SAS backplane, they are NOT interchangeable)
Users browsing this forum: No registered users and 6 guests