PCIe x8 RAID controller in x16 slot?

saiyan

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I am thinking about buying a PCIe x8 RAID controller (ie ARC-1210) and plug it into one of the x16 slot of a NForce4 SLI motherboard I'm planning to buy. The specifications of various NForce4 SLI motherboards I have seen all indicate that the two x16 slots normally operate at x16 and x1 bandwidth respectively with a single x16 graphics card but will operate in only x8 and x8 bandwidth in SLI mode.

So if I "up plug" an x8 RAID controller into the second x16 slot, is it going to operate at x1 bandwith only?
That is still better than a PCI-X or 64-bit PCI controller sitting in a 32-bit/33mhz PCI slot though.
Is there any NForce4 motherboard that can operate both x16 slots, not necessary in SLI mode, in full bandwidth?

Thanks.
-jl
 
saiyan said:
I am thinking about buying a PCIe x8 RAID controller (ie ARC-1210) and plug it into one of the x16 slot of a NForce4 SLI motherboard I'm planning to buy. The specifications of various NForce4 SLI motherboards I have seen all indicate that the two x16 slots normally operate at x16 and x1 bandwidth respectively with a single x16 graphics card but will operate in only x8 and x8 bandwidth in SLI mode.

So if I "up plug" an x8 RAID controller into the second x16 slot, is it going to operate at x1 bandwith only?
That is still better than a PCI-X or 64-bit PCI controller sitting in a 32-bit/33mhz PCI slot though.
Is there any NForce4 motherboard that can operate both x16 slots, not necessary in SLI mode, in full bandwidth?

Thanks.
-jl

Your info is a little off when you switch the mobo (flip the card, jumpers or set in bios) to SLI (for dual video) then both 16x Slots work at 8x and 8x. At this point you can then plug in what ever you want in it. In your case your 8x Raid card will work exactly as a 8x Raid card.
 
yes, put it in SLI mode, giving both slots x8 capabilities. also, your video wont take a hit because all the x8 bandwidth isnt fully occupied even with the most current games.
 
The real question is how many HDDs would have to be in the raid array to saturate a 1xPE slot? 1xPE does 250MB/s. Is this board for SCSI? SATA? 1 SATA bus is 150MB/s tansfer rate. That's 2 drives. How many busses does this thing support?

Then there's the core of the issue, physical drive capabilities. 1 Maxtor Diamond Max 10 (used for reference since it's the fastest mainstream model around) can only sustain about 50MB/s data transfer. Now you're looking at 5 drives running full bore all at once to saturate a 1xPE line. You're probably thinking some sort of RAID 0 or RAID 0+1 so that's 2 or 4 drives (unless you're sick and want more). That leaves at least 50MB/s unused bandwidth on a 1xPE line. Unless some very reliable banchmarking can be provided to the contrary, I wouldn't even bother with anything more than 1x unless you plan on using more than 4 drives on the array.
 
Switching the slots to SLI will not allow your PCIe adaptor to work at 8x.

Currently, I know of no mobo that allows both slots to operate at full speed.
 
After a little research, it looks like only NForce Professional chipset provides two full bandwidth x16 slots. Unfortunately all motherboards featuring this chipset are all designed for socket 940 CPUs.

The RAID controller I am considering to buy is ARC-1210 which is a SATA II RAID controller using PCIe x8 interface and features Intel IOP332/333 processor.

If I do get the card, I will probably follow ViN86's suggestion and run the two x16 slots in SLI mode and see how the RAID controller and the video card performs.
 
AceGoober said:
Switching the slots to SLI will not allow your PCIe adaptor to work at 8x.

Currently, I know of no mobo that allows both slots to operate at full speed.
ummm, its an SLI board. in single video, it allows on x16 connection. when switched to SLI it allows two x8 connections. theres not enough connections on the nforce4 chip to allow two x16 connections.

id ignore that post, he runs an AGP mobo on with an intel chip.....

only opteron boards with two chipsets offer that functionality, but he only needs an x8 connection.
 
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