PCIe x16 slots

JohnJSal · 12-15-2007, 01:26 AM

What is meant when the specs of a mobo say something like this:

2 PCI Express X16 slot(x16, x4)

or

1 x PCI-E X16, 1 x PCI-E X16 (x4 bandwidth)

as opposed to just saying it has 2 x16 slots? Is there a difference in one of the slots when the above is listed? Does it affect dual GPU performance?

oregon · 12-15-2007, 01:34 AM

Yeah... it means the slot is limited to x4 performance when both slots are used. So yes, it probably would affect the performance and you do not want that if you plan on using two cards.

JohnJSal · 12-15-2007, 01:37 AM

Quote:

Originally Posted by oregon

Yeah... it means the slot is limited to x4 performance when both slots are used. So yes, it probably would affect the performance and you do not want that if you plan on using two cards.

Thanks. So if only one slot is used, would either of them run at x16 (or do you have to use the "proper" one)? Also, if both are used, but not for SLI/CrossFire, do they both run at x16?

oregon · 12-15-2007, 01:41 AM

I'm assuming either would, but I don't know. It probably depends on the board.

I'd assume if both are used either one or both would run at x4. I don't know whether using crossfire/sli or not would make a difference.

JohnJSal · 12-15-2007, 01:44 AM

Quote:

Originally Posted by oregon

I'm assuming either would, but I don't know. It probably depends on the board.

I'd assume if both are used either one or both would run at x4. I don't know whether using crossfire/sli or not would make a difference.

Well, it sounds like something I might want to stay away from anyway. Good to know it does mean something different than normal.

techgeek101 · 12-15-2007, 04:59 AM

Quote:

Originally Posted by JohnJSal

Well, it sounds like something I might want to stay away from anyway. Good to know it does mean something different than normal.

If its not SLI or crossfire certified you may not want to bother buying it.

[-0MEGA-] · 12-15-2007, 05:27 AM

It means the primary slot runs at x16 speed, however the second slot is physically a PCI-E x16 slot, however only provides the bandwidth of a 4x slot.

12-15-2007, 01:26 AM	#1 (permalink)
JohnJSal Platinum Member Join Date: Nov 2007 Location: Hoboken, NJ Age: 28 Posts: 527	PCIe x16 slots What is meant when the specs of a mobo say something like this: 2 PCI Express X16 slot(x16, x4) or 1 x PCI-E X16, 1 x PCI-E X16 (x4 bandwidth) as opposed to just saying it has 2 x16 slots? Is there a difference in one of the slots when the above is listed? Does it affect dual GPU performance?

12-15-2007, 01:34 AM	#2 (permalink)
oregon Platinum Member Join Date: Jun 2007 Location: portland, oregon Posts: 923	Yeah... it means the slot is limited to x4 performance when both slots are used. So yes, it probably would affect the performance and you do not want that if you plan on using two cards. __________________ MB: Gigabyte P35-DS3L CPU: Core 2 Duo E6550 @3.5hz GPU: PNY GeForce 8800 GT 512 RAM: 4GBs DDR2-800 (Ballistix and OCZ SLI) CL4 PSU: Antec NeoPower 650W Case: Antec 900 HDD: Seagate SATA 250GB, 16MB cache Seagate SATA 320GB, 16MB cache

12-15-2007, 01:41 AM	#4 (permalink)
oregon Platinum Member Join Date: Jun 2007 Location: portland, oregon Posts: 923	I'm assuming either would, but I don't know. It probably depends on the board. I'd assume if both are used either one or both would run at x4. I don't know whether using crossfire/sli or not would make a difference. __________________ MB: Gigabyte P35-DS3L CPU: Core 2 Duo E6550 @3.5hz GPU: PNY GeForce 8800 GT 512 RAM: 4GBs DDR2-800 (Ballistix and OCZ SLI) CL4 PSU: Antec NeoPower 650W Case: Antec 900 HDD: Seagate SATA 250GB, 16MB cache Seagate SATA 320GB, 16MB cache

12-15-2007, 05:27 AM	#7 (permalink)
[-0MEGA-] Diamond Member Join Date: Nov 2004 Location: Concord, NH Age: 19 Posts: 26,897	It means the primary slot runs at x16 speed, however the second slot is physically a PCI-E x16 slot, however only provides the bandwidth of a 4x slot. __________________ Desktop // Laptop Core 2 Quad Q9550 @ 4.0GHz // Core 2 Duo T9300 2.5GHz Asus Rampage Formula X48 // Intel PM965 ATI 4870X2 2GB GDDR5 // Dual 512MB GDDR3 8600M GT's SLI 4GB (2x 2GB) DDR2 940 // 3GB DDR2 667 DC 750GB SATA 3.0Gbps w/32MB // 400GB (2x 200GB) 7200RPM Creative SB X-Fi Titanium Fatal1ty SilverStone 750W +12V@60A 3DMark06: 21366 // 7394

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