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R7 370 2GB crossfire installed; comp no longer POST

Question asked by grov3rgil on Sep 7, 2015
Latest reply on Sep 7, 2015 by backFireX64

Friday I installed new RAM and new GPUs on my motherboard. I contacted the mobo manufacturer about the RAM and GPUs to ensure compatibility before I made the purchase. I ensured the RAM was supported by my processor. I built this system in 2011 and have done nothing to it since then. One rule I failed at was installing one piece at a time. I don't know if this is an actual rule, or just something I did in the past.

 

At any rate, I plugged my PSU back in and turned on the computer. At first my screen froze on the ROG banner during POST. The LED on my mobo showed an error at CPU (the last of five LEDs). I put the original hardware back in, and got the same result. Now, the LED stops on the first check CPU_PLL. I see that this  is some kind of voltage protection for the CPU. Great, but why now? I also have an amber LED near my HDD SATA connection. It doesn't matter what hardware I have in the case. Old, new, combination, one GPU, two GPUs, two xfire GPUs. It doesn't matter. I tried using the 6+2 pin connections from separate PCIe power sources, or the one that has two from the same line. No change. One thing I have noticed is when the older GPUis installed, the PSU fan runs much, much, much faster than it does with the new VGA installed. The case fans run slow no matter what. The CPU cooler fan seems to be running as it always had.

 

A buddy of mine who helped me build this thing in 2011 told me I might have a PSU problem. He said my PSU is SLI-ready, but I am trying to run Crossfire. I don't understand that from a power perspective, but what ever. Several forum posts I have read suggest there is no difference between SLI support and Crossfire support, as far as PSUs are concerned. I do not think my system is encroaching anywhere close to 750 watts which leaves me bewildered. I wish I had another PSU to test with. I feared I had fried my processor, but I do not think this is the issue.

 

I cannot get to the BIOS. I cannot get anything on my monitor.

 

Does it matter that my mobo has PCIe 2.0 but the GPUs want 3.0?

 

Old Setup:

Intel i5 661 3.3 GHz (never OC'ed) (LGA1156 socket)

ASUS Maximus III ROG (P55 chipset)

CoolIt ECO ALC contained liquid CPU cooling system

Corsair DDR3 1600MHz 8GB (4x2) 1.65v

ASUS ATI Radeon HD 5770 1GB (running solo)

Antec HCG 750w PSU

Western Digital Green Caviar 1TB HDD

 

New Setup:

Intel i5 661 3.3 GHz (never OC'ed) (LGA1156 socket)

ASUS Maximus III ROG (P55 chipset)

CoolIt ECO ALC contained liquid CPU cooling system

G-Skill Ripjaws DDR3 1333MHz 16GB (4x4) 1.50v

ASUS ATI Radeon R7 370 (crossfire)

ASUS ATI Radeon R7 370 (crossfire)

Antec HCG 750w PSU

Western Digital Green Caviar 1TB HDD

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