We went through a couple of sample cards from Gigabyte, and both exhibited the same screeching under load, prompting Gigabyte to investigate further. The company apparently traced the issue back to a batch of bad electrical components—chokes, specifically—that it had received from one of its vendors. This batch of bad chokes didn't affect every GV-NX86S256H sold, but both our samples came from an inflicted batch, so Gigabyte sent us a fresh card for testing.
I've had that card cranking on Oblivion for several hours now in blissful silence, so it appears that the problems we had with our initial samples have been resolved. This passively-cooled GeForce 8600 GTS is indeed silent, and when you consider that it also comes bundled with a copy of Supreme Commander and a street price of around $183, the GV-NX86S256H is a pretty sweet deal.
Passive cooling may be silent, but it still runs the 8600 GTS a little hot. This new card's GPU hits 90C under load. That's cooler than our initial samples, but it's still pretty toasty when compared cards that benefit from active cooling. The GV-NX86S256H's power consumption is also a little higher than that of its rivals under load, likely because Gigabyte has opted to rely on the PCIe x16 slot exclusively for power rather than using an auxiliary six-pin power connector.Since our 8600 round-up, we've also received one of Gigabyte's passively cooled GV-NX-86T256H GeForce 8600 GT cards. This card comes with 600MHz core and 720MHz memory speeds that should yield a nice little performance boost over stock-clocked GT cards at 540MHz core and 700MHz memory. The GV-NX86S256H doesn't use Gigabyte's Silent Pipe 3 cooler, though. Instead, it opts for a single-slot design that won't cannibalize adjacent expansion slots. The GT card's cooler is a little longer and taller than that of the GTS, but it's also much lighter.
We haven't run this GT card through a full suite of tests, but it, too, has cranked through several hours of Oblivion stress testing. Interestingly, the card develops a subtle hum under load—not a whine or a shriek, but a low buzz that's still under the minimum 40-decibel noise level detectable by our digital sound level meter. This hum disappears at idle and may only be audible if the rest of your system's components flirt with absolute silence.
As with its GTS counterpart, Gigabyte's 8600 GT runs pretty hot—up to 106C after an hour and a half of a high resolution, high detail Oblivion stress test. At 158W under load, power consumption is also higher than we've seen from other GT cards. However, given the GV-NX86S256H's 600MHz core clock speed and single-slot cooler, those results aren't entirely surprising or unreasonable. Testing was also conducted on an open test bench that doesn't have any ambient airflow to whisk warm air away from the card's passive heatsink.
With a street price of just $130 and the same Supreme Commander game bundle as its GTS big brother, the GV-NX86S256H looks like another attractive option if you're in the market for a quiet GeForce 8600-series graphics card. Just keep in mind that passive cooling tends to run mid-range GPUs pretty hot, so you'll want to have at least some enclosure airflow circulating around the graphics card.