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Krisnatharok
PC Builder, Gamer
Premium Member
join:2009-02-11
Earth Orbit

Krisnatharok

Premium Member

Re: Proposed Mother of All Builds (MOAB)

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424w under max load @ stock; peaked at 520w with OCs

SSD speeds

New top Valley score for Extreme HD setting

Moos
Tequilablob
Premium Member
join:2008-12-11
Salt Lake City, UT

Moos

Premium Member

Looks Nice! When's the second GPU going in?

Krisnatharok
PC Builder, Gamer
Premium Member
join:2009-02-11
Earth Orbit

Krisnatharok

Premium Member

said by Moos:

Looks Nice! When's the second GPU going in?

Ordered today, but shipping from CA, so probably in about 5 days. I'm pretty excited, and I am going to tune this rig to come close to maxing out my PSU.

My max draw with a single card is 520w at the wall (CPU@4.6 GHz, GPU @ 1220 Mhz), which is about ~470w internally. A second GPU will add 250-300w max, so I'll tune both GPUs with a mild OC to peg the PSU at 750w.

Since it is a Corsair AX series, I don't have an issue with letting it max out under full load (OCCT PSU test running LINPACK and FURMARK simultaneously)--everyday usage will be much less.

If I was buying a new PSU, I'd probably have gone with an 850w, but I see no issue with running the AX750 since I already own it.
Krisnatharok

Krisnatharok

Premium Member

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»/r0/do ··· core.jpg

The difference between one GPU OC'd, and two at stock speeds.
Krisnatharok

Krisnatharok

Premium Member

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And Crossfire OC'd (1150mhz core / 1550 mhz mem). I shit you not, I had to run this twice to make sure it wasn't a fluke, and they were within a couple points of each other.
Krisnatharok

Krisnatharok

Premium Member

As requested, Crysis 3 benchmarks

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2560x1440
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1920x1080
I'll be the first to admit this makes no sense. My average FPS more than doubles when I go Crossfire. But I ran the benchmark several times, using the same scene for all three tests.

The only thing I can think of is that I got a Rev2 Vapor-X that requires 2x PCIe 8pin adapters, whereas my original Vapor-X requires 1x 6pin and 1x 8pin. I moved the first GPU to the second slot and put the 2x 8pin card in my first PCIe slot, which makes it the primary/master slot.

So it's possible that Sapphire has significantly increased the power of the 7970 3GB Vapor-X. *shrug*

GPU clocks for:
i7-920: 1215 mhz core / 1635 mhz memory
i7-3770K: 1220 mhz core / 1600 mhz memory
i7-3770K Xfire: 1150 mhz core / 1550 mhz memory

tl;dr 7970s overclock amazing well, and the scaling in Crossfire is just stupid good.
Krisnatharok

Krisnatharok

Premium Member

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Two Sapphire Radeon 7970 3GB Vapor-X's!
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Hmmm.... Rev2?
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Derp cable adapters
Sooooo funny story. Even though my CPU ships with 4x PCie 8pin cables, you can only use 2 of them if you also use the extra CPU power pins (2x 4+2pin).

So I ended up looking like the idiot and using the included molex-to-PCIe adapters. It looks horrendous, and I'm not sure it's the greatest way to power the cards, but I am only pulling 560w MAX at wall with the lighter OCs (4.2 GHz CPU, 1150mhz GPU core, 155mhz GPU mem), and it doesn't matter if it's in Furmark, Crysis 3, or Unigine Valley.

I'll probably buy some cable extenders to tidy things up, but as they say... BUILD COMPLETE motherfuckers.

Raible
join:2008-01-23
Plainfield, IN

Raible to Krisnatharok

Member

to Krisnatharok
I find it interesting the CPU did little to nothing for you.

Ghastlyone
Premium Member
join:2009-01-07
Nashville, TN

Ghastlyone

Premium Member

said by Raible:

I find it interesting the CPU did little to nothing for you.

His first benchmark posted a score of 1,792 (in the Crysis benchmark thread). With the new Ivy Bridge 3770k installed, same GPU, Kris posted a score of 2,086.

So it was about a 15-16% increase with just the CPU.