Advice on motherboard for a 3-4 GPU

[whoacowboy]

Hi,

I decided to build a hackintosh for 3D rendering, and I'd like to get 4 GPUs but am willing to get as many as possible.

My config is looking like this:

3-4 Nvidia Titan Xp's (need Iray)
Intel Core i7 6700K 4.00 GHz
32 GB DDR4 (Ballistix Sport LT 32GB Kit)
EVGA 1000 GQ, 80+ GOLD 1000W

I am stuck finding a Motherboard. I believe I want it with Scalable Link Interface (SLI), but I am unclear if that is only for gaming. I really just want the cuda cores, so if I don't need it.

I really just want the easiest build install possible. Any guidance is appreciated.

Thanks, james

 

[trs96]

I put your proposed build with 4 Titan XP and a 6700K + liquid cooler + 32 GB ram into a PSU calculator and this is the result I got:

If you only go with 3 Titans then a 1000W might be enough but it's still cutting it close.
I would get a 1200W PSU just to be on the safe side.

 

[whoacowboy]

I put your proposed build with 4 Titan XP and a 6700K + liquid cooler into a PSU calculator and this is the result I got:
View attachment 285462
If you only go with 3 Titans then a 1000W might be enough but it's still cutting it close.

Thanks, this is great.

I did some research and it looks like GIGABYTE AORUS GA-Z270X-Gaming 9 would work. Hoping to get something less expensive.

 

[trs96]

This is the best value in high end Platinum PSUs currently.

https://www.newegg.com/Product/Product.aspx?Item=N82E16817151163&cm_re=seasonic_1200w-_-17-151-163-_-Product

 

[Jamesbond007]

Thanks, this is great.

I did some research and it looks like GIGABYTE AORUS GA-Z270X-Gaming 9 would work. Hoping to get something less expensive.

Don't expect a cheaper motherboard to satisfy what you want, unless you are ready to compromise and accept PCIe x4 bandwidth for some or all of the graphics cards you want to use.

The 6700K and Skylake platform only provides 16 PCIe 3.0 lanes from the CPU for graphics (and may be other) uses. 4 graphics cards means that each of them only has 4 lanes of PCIe 3.0 for uses (x4 bandwidth), which may reduce the performance of the cards significantly.

The GA-Z270X-Gaming 9 motherboard has extra hardware to provide extra PCIe lanes for graphics card use and that's why it is able to provide x8 bandwidth (a total of 32 PCIe lanes) for use by each of the 4 graphics cards. This extra hardware costs quite a bit of money.

 

[whoacowboy]

Don't expect a cheaper motherboard to satisfy what you want, unless you are ready to compromise and accept PCIe x4 bandwidth for some or all of the graphics cards you want to use.

The 6700K and Skylake platform only provides 16 PCIe 3.0 lanes from the CPU for graphics (and may be other) uses. 4 graphics cards means that each of them only has 4 lanes of PCIe 3.0 for uses (x4 bandwidth), which may reduce the performance of the cards significantly.

The GA-Z270X-Gaming 9 motherboard has extra hardware to provide extra PCIe lanes for graphics card use and that's why it is able to provide x8 bandwidth (a total of 32 PCIe lanes) for use by each of the 4 graphics cards. This extra hardware costs quite a bit of money.

So what processor would you recommend?

 

[Jamesbond007]

So what processor would you recommend?

(1) The older X99 platform together with a CPU like the Core i7 6850K, which is a 6 core CPU with 40 PCIe 3.0 lanes, meaning that with a suitable X99 motherboard you can have 4 graphics cards each using x8 bandwidth and there is still 8 lanes available for other uses such as a NVMe SSD. But this platform is being phased out and replaced by the X299 platform.

(2) The X299 platform, newly available from June, together with a CPU like Core i7 7800X (6 cores) / Core i7 7820X (8 cores), both with 28 PCIe 3.0 lanes, or a Core i9 7900X (10 cores) with 44 PCIe 3.0 lanes.

The CPUs are (much) more expensive than a Core i7 6700K or 7700K, and the motherboards may not be much cheaper than the Z270X-Gaming 9. And both these platforms are not natively supported in MacOS, although support for the X299 platform may come when Apple releases the iMac Pro in December and the new Mac Pro in 2018. Some people have success in using the X99 and X299 platforms in MacOS and you can search in the forums for examples.

In conclusion, I believe going with that Z270X-Gaming 9 motherboard may be your best bet, but you have to pay for it.

 

[whoacowboy]

(1) The older X99 platform together with a CPU like the Core i7 6850K, which is a 6 core CPU with 40 PCIe 3.0 lanes, meaning that with a suitable X99 motherboard you can have 4 graphics cards each using x8 bandwidth and there is still 8 lanes available for other uses such as a NVMe SSD. But this platform is being phased out and replaced by the X299 platform.

(2) The X299 platform, newly available from June, together with a CPU like Core i7 7800X (6 cores) / Core i7 7820X (8 cores), both with 28 PCIe 3.0 lanes, or a Core i9 7900X (10 cores) with 44 PCIe 3.0 lanes.

The CPUs are (much) more expensive than a Core i7 6700K or 7700K, and the motherboards may not be much cheaper than the Z270X-Gaming 9. And both these platforms are not natively supported in MacOS, although support for the X299 platform may come when Apple releases the iMac Pro in December and the new Mac Pro in 2018. Some people have success in using the X99 and X299 platforms in MacOS and you can search in the forums for examples.

In conclusion, I believe going with that Z270X-Gaming 9 motherboard may be your best bet, but you have to pay for it.

Thanks! I will let you know how it goes.

 

[whoacowboy]

(1) The older X99 platform together with a CPU like the Core i7 6850K, which is a 6 core CPU with 40 PCIe 3.0 lanes, meaning that with a suitable X99 motherboard you can have 4 graphics cards each using x8 bandwidth and there is still 8 lanes available for other uses such as a NVMe SSD. But this platform is being phased out and replaced by the X299 platform.

(2) The X299 platform, newly available from June, together with a CPU like Core i7 7800X (6 cores) / Core i7 7820X (8 cores), both with 28 PCIe 3.0 lanes, or a Core i9 7900X (10 cores) with 44 PCIe 3.0 lanes.

The CPUs are (much) more expensive than a Core i7 6700K or 7700K, and the motherboards may not be much cheaper than the Z270X-Gaming 9. And both these platforms are not natively supported in MacOS, although support for the X299 platform may come when Apple releases the iMac Pro in December and the new Mac Pro in 2018. Some people have success in using the X99 and X299 platforms in MacOS and you can search in the forums for examples.

In conclusion, I believe going with that Z270X-Gaming 9 motherboard may be your best bet, but you have to pay for it.

So I got the Z270X-Gaming 9 up and running high sierra, woo hoo. I had two GPUs to start. I bought the other two, install them and booted up and I got a "couldn't allocate runtime area". I uninstalled the 4th GPU and everything booted up fine.

Is this the processor issue you were talking about?

I have the I7-6700K LGA1151 which supports
Up to 1x16, 2x8, 1x8+2x4

It looks like the Intel® Core™ i7-7700K Processor supports the same.

 

[Jamesbond007]

So I got the Z270X-Gaming 9 up and running high sierra, woo hoo. I had two GPUs to start. I bought the other two, install them and booted up and I got a "couldn't allocate runtime area". I uninstalled the 4th GPU and everything booted up fine.

Is this the processor issue you were talking about?

I have the I7-6700K LGA1151 which supports up to 1x16, 2x8, 1x8+2x4.

It looks like the Intel® Core™ i7-7700K Processor supports the same.

No idea. The CPU (6700K and 7700K) and the Z270 chipset by itself supports up to 1x16, 2x8, 1x8+2x4, but the motherboard has hardware that enables support up to 4x8, according to the motherboard specifications :

1. 2 x PCI Express x16 slots, running at x16 (PCIEX16_1, PCIEX16_2)
   * For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16_1 slot; if you are installing two PCI Express graphics cards, it is recommended that you install them in the PCIEX16_1 and PCIEX16_2 slots.
2. 2 x PCI Express x16 slots, running at x8 (PCIEX8_1, PCIEX8_2)
   * The PCIEX8_1 slot shares bandwidth with the PCIEX16_1 slot and the PCIEX8_2 slot with PCIEX16_2. The PCIEX16_1/PCIEX16_2 slot operates at up to x8 mode when the PCIEX8_1/PCIEX8_2 is populated.
   (All of the PCI Express x16 slots conform to PCI Express 3.0 standard.)

Can you make do with 3 rather than 4 GPUs at this time?