Build, Heat, and Noise

Given that the iBUYPOWER Erebus GT we have for review now is essentially identical in terms of build quality to the one we reviewed a month-and-a-half ago, there isn't a whole lot to update on. Build quality on this review unit was excellent, period, and the components iBUYPOWER chose were all solid, name brand selections. If anything, I think part of it might have been over-engineered.

Where things get interesting is when we look at system thermals and power draw. We've heard that Ivy Bridge runs hotter than Sandy Bridge does, and I can confirm those findings by comparing the thermal readings from our Sandy Bridge-based Erebus GT against our Ivy Bridge-based Erebus GT.

Intel Core i7-2700K-based Erebus GT

Intel Core i7-3770K-based Erebus GT

First, it's pretty obvious the water-cooling loop is doing its job on the video cards, and by doing so they give NVIDIA's GPU Boost a lot of thermal leeway. iBUYPOWER didn't overclock the GTX 680s in the Erebus GT, but odds are good you could probably eke out even more performance if you were somehow not satisfied with two GTX 680s in SLI. Second, the i7-3770K definitely runs hotter than the i7-2700K. Not by a tremendous degree, but there's a difference. Keep in mind that the ambient temperature in the room when testing the i7-3770K was closer to 21C, and definitely lower than it was when testing the i7-2700K.

Something to consider is that Ivy Bridge is a smaller chip than Sandy Bridge, but while it's more power efficient (see below), it's also more power dense. If we just use the base TDP, Sandy Bridge 4C is 95W in a 216mm2 die, for a power density of 0.44W/mm2. Ivy Bridge 4C by comparison is 77W in 160mm2, or 0.48W/mm2. That's only a 9% increase, but given how IVB reacts to overclocking and voltage, it's not too surprising that maximum reasonable overclocks are down for this first round of 22nm parts.

I'll say I'm not sure that HWMonitor's wattage readings are 100% accurate, either; the 203W it reports for the overclocked i7-2700K doesn't line up with our own power consumption test results, while HWMonitor reported between 50W and 70W for the i7-3770K. That's a little more believable given how frugal this configuration was with power in our test results, but still seems on the low side.

In terms of noise, it seems like someone heard my complaint about the fans in the first Erebus GT because this one comes with a fan controller. iBUYPOWER employs NZXT's six-channel analog fan controller, and it's very easy to adjust fan speeds to strike a good balance between noise and performance. I use the same controller in my own personal desktop.

Power Consumption

Where things get really exciting, actually, is in how much power this Erebus GT pulls from the wall. Keep in mind we're still dealing with a custom liquid-cooling loop, but thankfully iBUYPOWER applies an offset voltage that allows the system to idle properly.

Idle Power Consumption

Load Power Consumption

Power consumption is, frankly, outstanding. Intel's i7-3770K, at least overclocked where it is in this system, still sips power, and the pair of GTX 680s are able to provide performance comparable to or better than a pair of GTX 590s at roughly half the power draw.

As a result, I honestly feel like the 1.2kW PSU is absolute overkill for the Erebus GT. It simply doesn't need it; a 750W unit would've done the job with plenty of headroom to spare. This configuration is incredibly efficient for the performance you get, so there's no need to waste the extra money on a huge power supply.

Gaming Performance Conclusion: Still a Solid Buy


View All Comments

  • Kimbernator - Friday, April 27, 2012 - link

    1200w for 2 680s? that's probably not wasteful.

    Never buy prebuilt gaming computers, building is cheaper and you'll get better performance.
  • Sabresiberian - Friday, April 27, 2012 - link

    Well, Nvidia's recommendations would put the PSU at 750W for 2 680s in SLI.

    You need some headroom if you plan to overclock the video cards, but I don't see that requiring another 450W. An 850W PSU should be more than plenty, unless you want room for installing 2 more cards, or 1 more card and plenty of room to OC the 3.

    You did read the test results showing max draw to be less than 500W, right?

    It's all good to say "never buy pre-built" when you personally have the time and inclination, and I more or less agree with the sentiment, but rigs like this one from iBUYPOWER are very much known quantities - everything in it is name-brand, and the unit itself has been tested here at Anandtech favorably. I wouldn't fault anyone for buying this rig over building his own.

  • DigitalWolf - Friday, April 27, 2012 - link

    "We've heard that Ivy Bridge runs hotter than Sandy Bridge does, and I can confirm those findings by comparing the thermal readings from our Sandy Bridge-based Erebus GT against our Ivy Bridge-based Erebus GT."

    The images that you have to compare the two systems... show the 2700k system with a maximum vcore of 1.06v and the 3770k with a maximum of 1.36v.

    I would expect the system with .3 higher vcore to run "hotter" even if they were the same chip...
  • Nickel020 - Friday, April 27, 2012 - link

    The same screenshot show that +12V is at a maximum of 7.03V... Don't put too much faith into software readings, especially with very hardware there are often errors. Given that the current value is 1.10V during idle, that 1.36V is likely just a freak reading, the VCore will not vary that much. Reply
  • Nickel020 - Friday, April 27, 2012 - link

    *with very new hardware there are often errors. Reply
  • leonzio666 - Friday, April 27, 2012 - link

    Where are Metro 2033, Mafia II, Witcher II with ubersampling and Crysis or Starcraft II MP benchmarks ??? No one, and I mean absolutely no one in their right mind would buy such a beast only to play the games tested. Reply
  • imaheadcase - Friday, April 27, 2012 - link

    No one buys a system for just the games YOU listed to. Games are subject to the user, the games they used are POPULAR games so they went with them.

    Starcraft MP does not stress a GPU/CPU much. Metro 2033 is not a game many play, Mafia 2 not many play, etc.
  • jonbanh - Friday, April 27, 2012 - link

    hmm, i would say starcraft 2 is pretty POPULAR. and if you say it doesnt stress the CPU/GPU enough, well you also have portal 2 up there hitting almost 300 fps. i would've liked to see metro 2033 also just because it's been one of the most demanding games so far. as well as crysis 2

    i always figured when systems are given to sites for reviews, the manufacturer provides "guidelines" for what benchmarks they want or dont want shown
  • Sabresiberian - Saturday, April 28, 2012 - link

    Oh yeah, popularity is always the top reason a game should be included in a benchmark suite.

    Dustin should have included "Angry Birds".

  • Tchamber - Friday, April 27, 2012 - link

    When do you expect to get the chance to compare 7970s in CF to the 680s in SLI? Reply

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