Advice buying SLI ready motherboards

jordfleet

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Jun 7, 2013
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10,510
Hey,

So it's that time for a rebuild again, and as always I like to pick up a few bargains in the just-out-of-date hardware.

Particularly with this build I want to be future proof which requires the motherboard to have USB3, SATA 3.0, DDR3 to at least 1600mhz. I have already picked up a GTX 460 768MB for about £30 and a stick of CMZ8GX3M1A1600C10B. However I want to avoid picking up a motherboard that wont allow me to connect in SLI as I intend to pick up another graphics card and an extra stick of RAM in the future.

Very simply, will they say in the specifications "SLI ready"? Silly question I know, but I assume CrossFire ready motherboards would not work without a bit of extra fiddling? Would I see any performance hit to get a 1-x16 PCIe and 1-x8 PCEi motherboard? Can any motherboard with the required slots be used to house two GTX 460s or must they be designed-for-purpose (thus requiring me to pay out an extra bit of moneys).

Also looking to stick with AMD CPUs. I believe the best chipset for my purpose is the AM3+? The FX-6xxx series are starting to become quite nicely affordable but I wonder is AM3+ compatible with AM3 CPUs? As (a little confusingly for me) it seems that some of the Phenom II x6's are outperforming the FX- series cards in the benchmark tests I've been looking at.


And finally, related to me build but not to motherboards. Would a two graphics card set-up require a power supply with four 6pin PCIe connectors? Assuming so, why do so many 800-900W PSUs around with a zillion amps across the 12V rails come with only 1PCe and and a handful of others... Can the 4pin molex's be split using splitters/adaptors safely so long as the PSU has enough power, or could this cause problems.


Many questions here I know, but thanks to anyone who spares the time to help out here. Just bear in mind with any suggestions that I'm looking to keep this build cost loooow. :)

J
 
Solution
All SLI-ready motherboards will come with an SLI connector and will say they are SLI-ready. You can see them in the images for a motherboard on a site like newegg.

SLI only works in x16 and x8 PCIe configurations.

For a PSU, the GTX 460 is rated to use a max of 160W:

http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-460/specifications

If you have two you're looking at 320W+ I always like to have at least 200W for the rest of the system (ie Fans, CPU, Disks). For the configuration you're describing above, if I were you, I'd get a minimum of 600W top-quality power supply. You don't want to skimp when it comes to power supplies at all. You don't want to load a system up with great components and then fry them with a $30...
Obviously if the motherboard advertises SLI ready than it should work right out of the box, but generally the motherboard doesn't care if your using an nvidia or AMD graphics card. If the mobo has multiple PCIex16 slots then you should be able to sli/crossfire.

Yes you can get 4 pin molex adapters to pci power connectors, it usually requires 2 X 4-pin molex to 1 pci power connector. Look for a powersupply that states it is SLI/Crossfire ready, they tend to come with 2 pci power cables but you would still need to do some converting for your second card if they both take two.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139040
 

jordfleet

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Jun 7, 2013
17
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10,510
So there's nothing particularly special about the motherboard other than just having another PCIe slot? So 1 PCIe 16x & PCIe 8x will work ok but perhaps with a bit of a performance drop on the 2nd card?

By splitting I meant more along the lines of going one 4 pin molex -> two 4pin molex -> PCI power connector (via adaptor). I have something like this in my current system but that's mostly just using it to power the case fans.
 
All SLI-ready motherboards will come with an SLI connector and will say they are SLI-ready. You can see them in the images for a motherboard on a site like newegg.

SLI only works in x16 and x8 PCIe configurations.

For a PSU, the GTX 460 is rated to use a max of 160W:

http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-460/specifications

If you have two you're looking at 320W+ I always like to have at least 200W for the rest of the system (ie Fans, CPU, Disks). For the configuration you're describing above, if I were you, I'd get a minimum of 600W top-quality power supply. You don't want to skimp when it comes to power supplies at all. You don't want to load a system up with great components and then fry them with a $30 1000W bargain-bin PSU. Seasonic is among the top-quality power supply producers out their. The Seasonic M12II 650W Modular power supply has 4 6+2 PCIe connections available. It could even power a system with 2 680s, so it can be used for future builds. It also has a 5-year warranty.

The reason the 12V rails is so vital and the PSUs seem to load the bulk of the power on this rail is because nearly everything in the system runs of the 12V rail.

As far as motherboards... It depends on your budget. Personally, I'd stick with Asus or Gigabyte as they tend to produce the top motherboards. The Asus M5A99FX Pro R 2.0 is a great qualiy board that will work with the Phenom IIs or the FX CPUs you're considering.

That being said... I'd get an Intel i5-3570K processor and an Asus P8Z77-V LK motherboard as the Intel platforms have proven to be the best with regard to gaming performance. Pricing is similar as well.
 
Solution

jordfleet

Honorable
Jun 7, 2013
17
0
10,510
Ah interesting. It seems even 4X would be sufficient for the GTX 460 (shame as I just missed an otherwise perfect motherboard go for £30 ;)). I'm thinking I like the look of the Gigabyte-9x0 AM3+ range as they seem to be quite reasonably priced and come with all the features I want.

Unfortunately most intel chips are way out of my budget as this whole build is hopefully going to come in under the £300 mark, which is including a new HDD, PSU & Case - failure of my current mass storage one is what's sparked this upgrade to begin with!


In terms of PSU is the general consensus that if it doesn't come with anywhere near enough connectors to begin with, you probably don't want to trust it even if it has more than enough power for what it's required to do?
 


Most low-end power supplies will have few connectors and many watts. That is something to look out for. But if you find a make/model and post it here, chances are one of us can tell you whether its worth picking up.