CrossFire, Overclocking & Temperatures
CrossFired HD 6770s
Well, we see both cards fit and work together in an X58 motherboard. Both HD 6770s are clocked at the default speeds of the mildly overclocked HIS IceQ X Turbo – 880/1250MHz and they give quite a performance boost in the Vantage chart below over a single HD 6770. The Catalyst Control Center allows both clocks to be fine-tuned and adjusted independently of each other. 890MHz was the highest overclock that CCC allowed for the HIS HD 6770 although the Gigabyte can be overclocked further.
CrossFire provides an impressive performance boost over a single HD 6770 and we also see nice scaling of the single cards with clock increases. What we next need to know is if the temperatures are safe as we overclock and CrossFire our mis-matched HD 6770s – one passively-cooled and once actively cooled.
Our ambient (room temperatures) were quite warm – 80F – so as to approximate a warm Summer day. Be aware that we used our Thermaltake Element G case which has excellent airflow for an oversized midtower.
To be totally fair, we turned the case fans to their very lowest rpms for both quietness and to not give our cards an unfair advantage over a hotter running case.
On a hot day, there is a big jump from idle temperatures to maximum load and overclocking definitely has an impact to raise temperatures. Yet we find that both HD 6770s run very cool and the massive heatsink of the passively-cooled Gigabyte does an awesome job of keeping the card cool – even as the top card in CrossFire.
The HIS IceQ Turbo X heatsink/fan does an excellent job of keeping the card cool and we never saw it spin up over 45% which meant that it was barely heard over the (very quiet) case and CPU fans. In fact, we noted a tiny bit of electrical noise coming from our passively-cooled Gigabyte when it was under extreme load – a slight ‘click’ with the ever-changing framerates. We are not certain if this slight noise is coming from our single sample or is in every card, but it is no deal breaker as it is still quieter overall than the HIS (or EVGA GTX 550 Ti).
Let’s head over to our conclusion.