Review: 55nm shows size does matter
Our today's guest is Geforce GTX 285, yet another card with a 55nm GPU. The recently announced GTX 295 card also features a 55nm GPU, as is the case with many other Nvidia cards such as the GTX 260 with 216 shaders. Nvidia opted for a silent approach, where the cards would get a new chip and retain the name without making a big fuss about it, but Geforce GTX 285 couldn’t retain the name as it was clocked higher than GTX 280.
Geforce GTX 280 has so far been the fastest single GPU Nvidia card running at 602MHz for the core and it packed a 65nm GT200 chip. The following picture shows the GTX 285 and the GTX 280 head to head. Gainward’s new card runs at reference core speed - 648MHz.
Although they appear to be somewhat identical, there’re a couple of things that will help you tell GTX 285 and GTX 280 cards apart. From this point of view we can see that GTX 285’s doesn’t feature protective rubber caps on SLI connectors, which is just fine as they weren’t needed in the first place except for better looking.
One of the best things that 55nm process brings is improved consumption, so the new GTX 285 requires only two 6-pin PCI Express connectors, whereas the 65nm GTX 280 required one 6-pin and one 8-pin connector. Nvidia claims that GTX 285 draws 204W at max, whereas the GTX 280 maxes out at 236W.
The coolers on both cards are almost identical whereas the backs of the cards are different. The black shielding is taken off, probably due to the fact that the new card features the memory only on the front side of the card. The card on the photo below is GTX 280, and you’ll find the memory to be located on the back of the card.
Both cards come with 1024MB of 512-bit memory running at 1242MHz (2484MHz effectively) on the GTX 285 and at 1107MHz (2214MHz effectively) on the GTX 280.
The core runs at 648MHz and the shaders at 1476MHz. If you compare them to GTX 280’s clocks (602MHz core and 1296MHz shaders) we see that the core got a boost of 46MHz. You’ll find the GPUz for GTX 280 cards below. GTX 285’s banwidth totals at 159GB/s, whereas GTX 280’s ends up with 141.7GB/s bandwidth.
It’s important to note that the new 55nm chip is technically not different from the old, 65nm chip.
240 stream processors on the GT 200 55nm chip feature 32 ROPs and the chip comes with GDDR3 memory support and 512bit memory interface. Here we have 8 ROP partitions each packing 4 ROP units (8 x 4 = 32 ROPs), where each ROP partition is connected to the main memory via a 64-bit connection. 8 ROP partitions x 64-bit interface equals 512bit memory interface.
The following photo shows the GTX 280 overclocked to match the GTX 285’s clocks. We checked our previous testing and found that when overclocked to these speeds, the old card performs close or equal to the new GTX 285. However, the new 55nm GPU runs cooler and consumes less energy in same tasks.
The GTX 285’s cooler is a bit improved in comparison to the GTX 280’s one. The rear part under the fan has more room for air to blow towards the power components and also points to their somewhat different layout.
The GPU is isolated better in this new cooler.
You’ll find the memory modules stacked around the graphics core, all 16 of them and each packing 64MB of memory.
G200-350-B3 denotes that the chip in question is GT200b made in 55nm production process.
The old chip has G200-300-A2 written on it. The following picture shows the GTX 280’s cooler.
We mentioned that GTX 285’s TDP is 204W, so apart from PCI Express slot’s 75W, this card needs additional two 6-pin PCI Express power connectors.
GTX 280’s PCB features one 6pin and one 8pin PCI-Express power connectors, totaling at a TDP of 236W.
Nvidia touts the GT200 (as well as G80 and G92) as multifunctional architectures capable of much more than just gaming. That means that we can put this card to other uses by utilizing Compute Unified Device Architecture (CUDA). One of the often mentioned apps capable of putting Nvidia’s GPU to good use is Badaboom, which converts videos using the stream processors’ parallel processing capabilities. That’s not all though, as Nvidia has more aces left up their sleeve, namely Stereoscopic 3D and PhysX.
Gainward’s packaging is large, but it will shield your card nicely in transport.
We see that Gainward bundled the SPDIF cable, which you’ll need if you want to use just one cable to bring audio and video to your HDTV. HDMI requires a DVI-to-HDMI connector, also bundled with the card. I/O panel features two dual link DVIs with HDCP.
Those who crave more can always resort to chaining up to three GTX 285 cards, as the card provides two SLI connectors.