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Tahiti LE, Tested: PowerColor's HD7870 PCS+ Myst Edition

Boost, Overclocking, And CrossFire

Clock Frequencies at Partial and Full Load

PowerColor's HD7870 PCS+ Myst Edition is pegged at its 925 MHz base clock rate when you push the Tahiti LE GPU really hard using general-purpose computing workloads. Games tend to be less taxing, giving the board some headroom to spend time at its 975 MHz Boost frequency. The higher clock rate isn't very consistent, though, particularly as you play through more demanding titles at higher detail settings.

Overclocking

Depending on your card and the rest of your system components, overclocking PowerColor's HD7870 PCS+ Myst Edition can increase its performance by 15% or more. We pushed the card's core clock all the way up to 1.2 GHz without touching its voltage. Setting PowerTune to +20% is all that it took to achieve a stable overclock.

This is pretty consistent with what we've seen from Radeon HD 7900-series cards. Our Pitcairn-based Radeon HD 7870 only makes it to 1,150 MHz.

There’s not much room to overclock the HD7870 PCS+ Myst Edition’s memory, though. We pushed it to exactly 1,600 MHz. Increasing the voltage is not a good idea, since the un-cooled RAM gets too hot. Besides, a 1,500 MHz factory setting is enough to prevent bandwidth bottlenecks from negatively influencing frame rates. If you care about the card's longevity, it’s better to just leave the memory frequency be.

CrossFire

PowerColor's HD7870 PCS+ Myst Edition shows its Tahiti roots when it comes to CrossFire configurations; you cannot pair it up to a normal Radeon HD 7870. Matching it up to any Radeon HD 7900-series card isn't a problem, though. In fact, we installed our review sample next to a HIS 7950 X², and we matched the performance level of the two cards by overclocking the PowerColor HD7870 PCS+ Myst Edition to 1.15 GHz. This gets us close to the same single-frame rendering times. However, if you leave both cards at their factory-set frequencies, you'll see a lot of micro-stuttering. Even RadeonPro couldn’t alleviate the issue, leaving us with dropped frames.

At $240 per card, two PowerColor HD7870 PCS+ Myst Edition boards make for a very competitive high-performance setup for less than $500. Now, let's take a look at power consumption.

  • mayankleoboy1
    Isnt this review quite a bit late ? IIRC, the card came ~1.5 months back...

    If it cant CFX with a 78xx, it has no right to be called a 7870+ . Marketing name fail +1.
    The chip by itself is fine, though.
    Reply
  • EzioAs
    That's quite a short review. It's not anything I haven't looked at other sites. Anyway, at the current price, I really have to agree the 7870XT (Tahiti LE) are excellent cards.
    Reply
  • EzioAs
    10449154 said:
    If it cant CFX with a 78xx, it has no right to be called a 7870+ . Marketing name fail +1.

    I agree. AMD has already establish good model naming scheme (X900 for high-end gaming, X800 for mid-range, X700 for low end gaming) after the 6000 series. To be honest, I say it's stupid not to call this chip the HD7930.
    Reply
  • Azn Cracker
    Or maybe the 7950 LE since its pretty much the same card just slower.
    Reply
  • hero1
    Azn CrackerOr maybe the 7950 LE since its pretty much the same card just slower.
    I agree with you on this one. Someone need to give these guys a call and tell them how it is. What a load of bs on their naming scheme. I would absolutely call this 7950 SS or LE!
    Reply
  • where are the frame time benches?
    Reply
  • FormatC
    The frametime thing (in some games) was gone (more or less) with the latest drivers and I think that AMD will handle the memory now a little bit better ;)
    Reply
  • shikamaru31789
    If only some other manufacturers were making these, Power Color's cooling solution isn't that good, 37.8 decibels while Gaming is not quiet enough for me.
    Reply
  • EzioAs
    10449161 said:
    If only some other manufacturers were making these, Power Color's cooling solution isn't that good, 37.8 decibels while Gaming is not quiet enough for me.

    Sapphire has one too, I believe
    Reply
  • shikamaru31789
    EzioAsSapphire has one too, I believeYeah, I just now noticed it on Newegg. Not sure why I didn't notice it before, based on the reviews it's been on there awhile. Too bad it costs $20 more than Power Color's. Still a good deal even at $260, since this review indicates that it's almost as fast as the much more expensive 7950's.
    Reply