Power Consumption, Temperature, Overclockability and Noise
As opposed to its predecessors that used to be just temporary solutions, the GeForce GTX 295 is meant to be a flagship product showcasing Nvidia’s technological superiority. Therefore such characteristics as power consumption, temperature and noisiness of this card are very important. That’s why we performed our usual tests on a specially configured testbed:
- Intel Pentium 4 560 CPU (3.6GHz, LGA775)
- DFI LANParty UT ICFX3200-T2R/G mainboard (ATI CrossFire Xpress 3200 chipset)
- PC2-5300 SDRAM (2x512MB, 667MHz)
- Western Digital Raptor WD360ADFD HDD (36GB)
- Chieftec ATX-410-212 PSU (410W)
- Microsoft Windows Vista Ultimate SP1 32-bit
- Futuremark PCMark05 Build 1.2.0
- Futuremark 3DMark06 Build 1.1.0
Following our standard method, the 3D load was created by means of the first SM3.0/HDR test from 3DMark06 running in a loop at 1600x1200 with 4x FSAA and 16x AF. The Peak 2D mode was emulated by means of the 2D Transparent Windows test from PCMark05. This test is important as it simulates the user’s working with application windows whereas Windows Vista’s Aero interface uses 3D features.
The transition of the G200 chip to 55nm tech process has had a positive effect on its electrical characteristics. As a result, the peak power consumption of the GeForce GTX 295 is no higher than 215 watts. This is far lower than the peak consumption of the Radeon HD 4870 X2. Contrary to all predictions, the GeForce GTX 295 is not a fire-spitting monster. ATI has got a reason to think about the efficiency of its technologies. It turns out that the pair of RV770 chips consumes far more power than two G200b chips manufactured on the same tech process, but the RV770 chips incorporate much less transistors!
As for the distribution of load, one of the PCBs of the GeForce GTX 295 is indeed powered by the 8-pin PCI Express 2.0 plug only whereas the other uses the 6-pin PCI Express 1.0 connector and the power lines of the PCI Express x16 slot. The chokes of the card’s voltage regulators produced an audible squeaking sound when under load. We don’t know if this is a normal thing for all GeForce GTX 295 or just a peculiarity of our sample. As for PSU requirements, Nvidia recommends using with this graphics card a 680W or higher power supply capable of delivering a combined current of 46A or higher across its +12V lines. This recommendation seems to be downright overstated in view of the power consumption data we’ve obtained. We guess the GeForce GTX 295 can be used with a high-quality 500-550 power supply safely enough.
We already know that the 55nm version of the G200 core has substantially better overclocking potential than the older version, so we attempted to overclock our sample of the GeForce GTX 295. Although EVGA had already per-overclocked it to 594/1296MHz core and 1026 (2052) MHz memory frequencies, we managed to increase them further to 650/1418MHz and 1200 (2400) MHz, respectively. That’s a good result for a card with two G200b chips cooled with a single, rather modest, heatsink. Unfortunately, we didn’t have enough time to benchmark the overclocked card in all of our tests and had to limit ourselves to Crysis, Far Cry 2 and 3DMark Vantage.
We kept track of the card’s temperature at the overclocked frequencies and found them to be as follows:
Well, if two cores are cooled with one heatsink, they must be hotter than a single such core. The card has higher GPU temperatures than single-core G200-based solutions even in 2D mode when the clock rates of both cores were dropped to 300/600MHz. The temperatures were high in 3D mode, but 82-86°C is not something extraordinary for today’s top-performance graphics cards. Our only apprehension is about the fact that not all of the hot air is exhausted by the card’s cooler outside. Some of it remains within the system case, so you should ensure that your gaming platform is ventilated properly if you want to install this card into it.
Despite the high component density and modest cooler, the GeForce GTX 295 has good noise characteristics for its class.
The reference cooler of the GeForce GTX 295 is not only quieter than the notorious cooler of the Radeon HD 4870 X2, but even quieter than the reference cooler of the GeForce GTX 280. The card is not silent, of course, but we could not make it increase the speed of its fan even during long tests. The spectrum of the noise is comfortable enough. It sounds like the hiss of the air whereas the incessant buzz of the fan’s motor in the noise from the Radeon HD 4870 X2 is really annoying. Thus, Nvidia is still superior when it comes to developing quiet and effective coolers for its graphics cards. Besides thinking about the disproportionally higher power consumption of its RV770 core, ATI should also think about the coolers. The reference coolers the company currently offers are not quiet at all.