When is 16 + 8 = 16? When you're advertising motherboards! BRING BACK X38/48

[Engineeringtech]

My Gigabyte socket 775, DDR2 motherboard never worked right from the day I bought it. Intermittent USB, Firewire, PCI, and Intel Matrix RAID. All symptomatic of a defective Southbridge. I can't say I got a three weeks use in the 19 months I owned it. It died 4 weeks ago, and I've been trying to find an appropriate "home" for my little used E8400, high speed DDR2, and RAID card. I've wasted at least a hundred hours looking for an X38, X48, or SLI board to match my components, with no luck. Sure a precious few are advertised, but they're either out of stock, used, "open box" or the price has been jacked way up.

I bought the board just a month or so before the economy tanked. I think I know now why Gigabyte stalled on replacing it. They never built enough of them to cover customer warranty. At least that's my theory....

So I've been looking at P45. Anyone but me think the industry's advertising is deceptive and misleading? Anyone try to use two PCI-e slots for something other than Crossfire or SLI?

x38 or x48 motherboards are advertised to have two PCI-e x16 slots. You get 16 + 16 = 32 PCI-e lanes, and the corresponding bandwidth.

But a P45 board? They advertise a PCI-e x16 slot and a PCI-e x8 slot. Apparently however, if you put an x8 card in the x8 slot, your x16 slot will be reduced to x8. I.E. 16 + 8 = 16 NOT 24! I don't want my either my x16 video card or x8 RAID card to be starved for bandwidth.

Not only that, but I have tried again and again to get a straight answer from Gigabyte, Asus, etc. as to whether you CAN put something other than another video card in the x8 slot. Does anyone else do this in a P45 card? The only thing the reviews talk about is Crossfire, or SLI.

[Psycho101]

Re: When is 16 + 8 = 16? When you're advertising motherboards! BRING BACK X38/48

You can put any card you like in the second PCIe slot, doesn't matter if it's a GPU, RAID Card, even a PCIe x1 sound card. It makes no difference. A PCIe slot is a PCIe slot.

As long as you're using a single GPU graphics card you won't have any issues at all with running the main slot at 8x. There isn't a GPU on the plannet that can saturate a 8x 2.0/16x 1.0 PCIe slot. Only when you get to dual GPU cards does PCIe 2.0 8x becoime not enough.

[Engineeringtech]

Re: When is 16 + 8 = 16? When you're advertising motherboards! BRING BACK X38/48

You can put any card you like in the second PCIe slot, doesn't matter if it's a GPU, RAID Card, even a PCIe x1 sound card. ............................As long as you're using a single GPU graphics card you won't have any issues at all with running the main slot at 8x. There isn't a GPU on the plannet that can saturate a 8x 2.0/16x 1.0 PCIe slot...........

Thanks for replying Psycho 101. Can you clarify some things for me? Does my 9800 GT video card only have a single GPU? And before I put my x8 hardware RAID card into the lower PCI-e slot, of the Asrock P45 board, should I configure the PCI slots as if I were were running a x8, x8 Crossfire video setup? Finally, would you know what is different about this Asrock P45 setup vs. Asus and Gigabyte boards? They don't seem to have a piggyback board to configure the PCI-e slots

[Psycho101]

Re: When is 16 + 8 = 16? When you're advertising motherboards! BRING BACK X38/48

Yes, your card has a single GPU. You'd definitely know if you bought a dual GPU card. Dual GPU's are popular with gamers and folders, they aren't mainstream at all.

I'm not sure about your particular motherboard, but usually it's a plug and play system. Any card detected in the second slot will force the other automatically down to 8x. There shouldn't be anything to do in the BIOS, it should just work. However you mention some sort of daughter board? I'd have to know details of your specific board to answer anything 100%.

[Engineeringtech]

Re: When is 16 + 8 = 16? When you're advertising motherboards! BRING BACK X38/48

Thanks again. Th emotherboard, an Asrock P45X3, which I haven't purchased yet, has a small pcboard which can be inserted in one of two directions. The manual says to insert it in one direction for Crossfire, and the other for non-Crossfire. It only mentions video cards, and that is why I didn't know if I could run my RAID card in it.

I'm pretty limited in choices for boards. Nothing much left out there with two PCI-e slots, support for 45 nm Intel socket 775 processors, and 1200 Mhz DDR. My only alternative seems to be a Asus P5N-D which is a 750 SLI board. From what I'm told the PCI-e slots work at x8 and x8 automatically when two video cards are inserted. I don't know what happens when you put in an x16 video card and x8 RAID card. Also, the DDR2 RAM support tops out at 800 MHz (my RAM is 1200 Mhz and I'd like to make good use of it).

[Psycho101]

Re: When is 16 + 8 = 16? When you're advertising motherboards! BRING BACK X38/48

Never seen anything like that before. Not sure why that board has that kind of daughterboard system. One would assume that you'd use it as it specified for non crossfire.

HAve you tried other online retailers rather than newegg? The choice seems a little restricted, but then again, sockewt 775 boards are EOL hardware. You may be better off saving some money and going second hand. As long as the seller has good feedback, ebay would be a good place to go. This way you won't be spending top dollar for old tech.

Note that because PCIe slots in many cases are used for graphics cards the specs will refer to them. However this does hold true for other PCIe cards too. In essence on a P45 that has two slots, any card inserted into the second PCIe slot will mean both slots run at 8x unless otherwise stated.