Overclocking

The R580 core on the X1900 GT should scale well, but also give up quite a bit of heat once you increase clock speeds, with the single slot heatsink you?ll run into a ?heat? wall rather quickly.

With the stock cooling the GT easily overclocked 634Mhz on the core (575Mhz default) and an impressive 801Mhz on the memory (600Mhz default), unfortunately the missing pixel shader processors could not be re-added, so in the end the performance is still below an X1900 XT, even when GPU/MEM are running faster on the overclocked GT.



In 3DMark2001SE & 3DMark03 (representing older games) the X1900 GT trails the 7900 GT when not overclocked; increasing the GPU/Memory allows it to catch up in 2001SE but not in 03.



In the newer benchmarks the X1900 GT is faster/on par with the 7900 GT and when overclocked the GT is almost catching up with the much faster XTX in 3DMark05. Let?s see what the overclock does in Oblivion:



13% increase in average FPS with the outdoor benchmark scene, not bad at all!



11% for the town/city benchmark, the overclock is certainly paying off in games as well, not only in synthetic benchmarks.

To get the most out of this X1900 GT without resorting to extreme cooling we swapped the stock cooler with a Zalman VF900Cu, this cooler when fed with enough cool air (read: good case cooling) will keep your card running cool and quiet!



With the new found cooling power we were ready to apply the overclocking tricks from our X1900/X1800 series OC guide on the GT. The core voltage was set to 1.270v and memory at 2.04v. This resulted in a final overclock of 668Mhz on the core and 828Mhz on the memory. With an increase of 16% on the core and an impressive 38% on the memory the X1900 GT from Powercolor has some overclocking headroom.


Noise and Temperatures

Unlike the 7900 GT from NVIDIA which has issues with fan speed control, the X1900 GT works as it should, in 2D mode it?s very quiet, not distinguishable from the ambient noise; in 3D mode the fan speed goes up steadily with the GPU temperature, in our hot test environment (thank you heat wave) with room temperature at 27?C the fan went up to 55% which resulted in 44.3dBA at 20cm which is only slightly lower than the Club 3D 7900 GT with its fan at 100%.

GPU temperature reached 93?C easily with the stock cooling, turning up the fan speed manually to maximum speed did reduce it drastically but noise went up and over 48.2dBA. With the Zalman VF900Cu cooling temperatures never passed 80?C with its fan at 12v (<40dBA).