Full SLI X16 and SLI is there a difference

[mediocer]

I want to get a MB that I can do SLI with. I have a 7800 GTX and plan on getting another when I upgrade.

I see MBs that say Full SLI X16 and others that say SLI.
Is there a difference?
Some reviews I have read say things like, this board is full SLI with X16 in both PCIe slots. Or others that say SLI compatible but, only first PCIe slot is X16 other is X8.

Could you please help me clarify this and lead me in the right direction?

Thanks in advanced.

 

[baracuda73]

The standard SLI is 8 pipelines per card and yours apparently is 16 pipelines per card.

 

[weskurtz81]

OK, when you use your PCI-E slot with one card, it is a PCI-E 16X slot. When you put two PCI-E cards in, it divides the bandwidth up, amongst the two cards. So basically, your motherboard has two PCIE 16 slots, and they don't divide the bandwidth up amongst the two cards. You have not problems

 

[nigelf]

OK, when you use your PCI-E slot with one card, it is a PCI-E 16X slot. When you put two PCI-E cards in, it divides the bandwidth up, amongst the two cards. So basically, your motherboard has two PCIE 16 slots, and they don't divide the bandwidth up amongst the two cards. You have not problems

you just beat me to the answer

A more complete answer:
the normal SLI motherboards split up the 16 lanes to 2 x 8 lanes when running in a SLI configuration. The "full x16 SLI" apparentely runs 2 x16 lanes in SLI (like this one). Now this sounds like a better solution but in reality for today gfx cards it does not make a difference (they cant even fill the 8 lanes). This might be interesting when not being able/ not wanting to run an SLI bridge.

Apart from that. you dont need SLI. The price increase (+ 100%) does not justify a small increase (max + 20%) to even decreases in avg. framerates. Stick to a NF4 (ultra) based mobo (like a DFI one). By the time you upgrade the next generation will be out and one new card will beat 2 SLIed cards (like 1 7900 GTX just outpaces 2 7800 GTX in SLI)

 

[mediocer]

Thx for all the help. This clarifies a lot.

By the time you upgrade the next generation will be out and one new card will beat 2 SLIed cards (like 1 7900 GTX just outpaces 2 7800 GTX in SLI)

Where did you find this info out. I'd like to read about it. It may save me some money.

 

[blader8901]

I would suggest you look at the interactive VGA charts right here on THG!

They are extreamly useful for situations like this, for example pick out SLI 7800gtx and a 7900 and compare the performance for games you like to play, this is very important as there is a large lack of consistancy between differrent games and how they handle SLI

for example the source engine is not very fond of SLI and will alot of time cause a decreae in performance over a single card where as other games such as battlefield 2 or quake 4 will yield as much as an 80 percent increase in performance, there are also alot of other factors to consider when getting SLI such as the resolution that you plan on playing games. Hihger resolutions generally gain more benifit from SLI then lower resolutions.

 

[nigelf]

... other games such as battlefield 2 or quake 4 will yield as much as an 80 percent increase in performance

But what difference does 100 to 180 fps make in gameplay.

Right now 1 ATI X1900XT munches though everything you can throw at it.