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Does it make a difference to use 2 x 8-pin connectors on the EVGA Classified?

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Revivalist

Member
Joined
Mar 27, 2005
Location
Fresno, CA
I'm not sure if this thread would fit better here or in the Intel Motherboard Section or even in the Power Supply section . . . But I figured it's most relevant to overclocking the i7 CPU. . .

To my knowledge, the EVGA Classified is one of the only motherboards that has 2 x 8pin CPU connectors . . .

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I was pleasantly surprised to discover that my PCPn'P has an extra 8-pin connector that has never been used.


TC1KWSR-harness_3834.jpg



I am guessing that the PSU was originally designed for a dual CPU situation. But this would be a perfect chance to make full use of what my PSU offers. So I'm happy about that. . . .

But I wonder if that will actually yield any real world difference when overclocking. My only thought is that maybe it will keep the voltage a little stiffer and less prone to fluctuation.

Then I read this webpage which says that an 8-pin connector is already capable of 336W. The CPU is not likely to use more than 220W even under load at 4.0GHz. (See this article.)

However, I figure that by spreading the power across more PSU wires and more traces on the motherboard, this could result in greater stability. For example, when the CPU is using 220W, with a 8-pin connector, each power wire is delivering about 4.6 amps. This is about 50% of the maximum 7 amps per wire. With two 8-pin connectors on the Classified, each wire is carrying about 2.3 amps which drops things down to about 25% of the maximum 7 amps per wire.

By the way, I was really surprised to learn in this article that by overclocking the CPU to 4.0GHz, the result is using 50% more power to accomplish the same task when running stock!!
 
I haven't tried that, so I can't really tell you what happen. But I did have a similar situation to my current Asus P5k-E motherboard. My motherboard comes with a 8-pin connector, but my old enermax noisetaker II 325 watt PSU only have 1 4-pin connector. I was able to hit 4.2ghz at 1.312v without any issues. Later I bought a Corsair VX400 power supply for $30 and it came with a 8-pin connector so I thought I will be getting better overclocks, but no. Everything remains the same where I did not get any benefit.

Old Enermax
CPU vcore = 1.3375v in BIOS, 1.32v idle, 1.312v load according to cpu-z
+3.3v = 3.25-3.26v in BIOS
+5.0v = 5.196-5.203v in BIOS
+12v = 12.196 - 12.202v in BIOS

New corsair VX400
CPU vcore = 1.3375v in BIOS, 1.32v idle, 1.312v load according to cpu-z
+3.3v = 3.32-3.33 in BIOS
+5.0v = 4.996 - 5.002v in BIOS
+12v = 12.174 - 12.186v in BIOS

I haven't tried with quad core CPU, but I don't think it will make a huge difference either. :shrug:
 
To spread the load ....

If you are an HARDCORE user and you OC the CPU to 5ghz + for benching, this second power line can be usefull. a 5ghz+ I7 can pump DAMN LOTS OF POWER !
 
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