Another can my GPU handle the crossfire

[Doligic]

Hello everyone!

I am about to receive 2 MSI R9 270x 4gb cards. I'm am just unsure as my PSU has 2 12v rails at 40 amps each on which rails to connect the 2 cards. My current specs and question explained below.

AMD FX 8150 (Overclocked to 4.3GHz at just under 1.4v, yes my chip requires more power than most to be stable)
Asus Sabertooth 990fx (first release on latest bios)
2x 4GB Gskill Sniper 1866 RAM
XFX 6950 2gb DD
Antec 902 Case
2x Cooler Master Jetflo 120
Corsair H80i (push/pull)
Samsung 840 Pro 256GB
External 1TB Seagate USB 3.0 drive
Antec HCG-850m PSU http://www.newegg.com/Product/Product.aspx?Item=N82E16817371067
+3.3V@25A, +5V@25A, +12V1@40A, +12V2@40A, -12V@0.5A, +5Vsb@3A

Currently I have everything minus my current XFX 6950 2gb card plugged into the 1st 12v rail as it is only partly modular. Only the 6950 is plugged into the 2nd 12v rail. I am not sure that 1 rail would be able to handle both R9 270x cards so I'm thinking put one on one rail and the other the other. But since I have an overclock on my FX 8150 I am worried that the 2 rails may not be able to supply the needed power.

I only use this machine for gaming on 3 Asus VS247 led monitors at 5760x1080. I'm thinking the best way to split the power is have 1 r9 270x and my cpu 8pin(modular) in 12v rail #2. And the other card and everything else in 12v rail #1. Is this going to work out great for me or am I going to possibly have to stock clock my 8150? Or possibly throw both r9 270x cards on 12v rail #2?

Sorry for the long post but I tried to get all my information and questions in. If I missed anything please just ask.

EDIT: I also used eXtreme Power Supply calculator and am showing 695w at 100% load but still doesn't help as to tell me what a r9 270x pulls at full load.

 

[nikoli707]

you will be fine, you have more than enough power.

 

[ko888]

For a system using two AMD Reference Design Radeon R9 270X graphics cards in 2-way CrossFire mode AMD specifies a minimum of an 750 Watt or greater system power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 43 Amps or greater and have at least four 6-pin PCI Express supplementary power connectors.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most critical factor.

Overclocking of the CPU and/or GPU(s) may require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock being attempted.

The Antec HCG M 850W (HCG-850M) power supply unit, with its maximum combined +12 Volt continuous current rating of 70 Amps and with four (6+2)-pin PCI Express supplementary power connectors, is way more than sufficient to power your system configuration with two Radeon R9 270X graphics cards in 2-way CrossFireX mode.

When using a single Radeon R9 270X the PCI-E cable should be plugged into the +12V1 modular connector on the PSU.

When using two Radeon R9 270X cards in 2-way CrossFire mode the primary card should be connected to +12V1 and the secondary card to +12V2.

 

[Doligic]

For a system using two AMD Reference Design Radeon R9 270X graphics cards in 2-way CrossFire mode AMD specifies a minimum of an 750 Watt or greater system power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 43 Amps or greater and have at least four 6-pin PCI Express supplementary power connectors.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most critical factor.

Overclocking of the CPU and/or GPU(s) may require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock being attempted.

The Antec HCG M 850W (HCG-850M) power supply unit, with its maximum combined +12 Volt continuous current rating of 70 Amps and with four (6+2)-pin PCI Express supplementary power connectors, is way more than sufficient to power your system configuration with two Radeon R9 270X graphics cards in 2-way CrossFireX mode.

When using a single Radeon R9 270X the PCI-E cable should be plugged into the +12V1 modular connector on the PSU.

When using two Radeon R9 270X cards in 2-way CrossFire mode the primary card should be connected to +12V1 and the secondary card to +12V2.

Thank you both ko888 and nikoli707 for putting my mind at ease