Fermi Goes Mobile: AVADirect's Clevo W880CU with GTX 480Mby Dustin Sklavos on July 7, 2010 11:45 PM EST
The Fastest Mobile GPU in the World: NVIDIA's GeForce GTX 480M
We'll cut to the chase: NVIDIA's GeForce GTX 480M does indeed reclaim the crown of fastest mobile GPU from ATI's strangely anemic Mobility Radeon HD 5870. And it ought to: after all, in a break with tradition the GeForce GTX 480M is actually properly named. The GPU core of the GeForce GTX 480M is indeed a Fermi GF100 lovingly crammed into a notebook form factor. NVIDIA cut that same 3.1 billion transistor you've all come to know and love down to a still-egregious 100-watt TDP, the highest of any mobile graphics hardware to date.
While the GeForce GTX 285M was just another rehash of the G92 and ATI's Mobility Radeon HD 5870 is a mobile version of their desktop Radeon HD 5770, NVIDIA's GTX 480M uses the same cut-down—but still Fermi—core found in desktop GeForce GTX 465 cards. That means 352 of NVIDIA's "CUDA cores" and a 256-bit memory bus connected to GDDR5 memory. The difference is that while the GTX 465 only gets 1GB of GDDR5, the GTX 480M gets a full 2GB in our review notebook. Clock speeds aren't as comparable, though, with the 480M's clock speed down from the GTX 465's 607 MHz to just 425 MHz. The shader clocks get cut down, too, dropping from 1.2 GHz to 800 MHz. Probably the most alarming drop is the GDDR5: running at 3.2 GHz on the desktop card, the 480M has its effective speed cut to just 2.4 GHz, the lowest speed we've ever seen on GDDR5 and actually a slower effective clock speed than the GDDR3 on the desktop GeForce GTX 285!
It's not unreasonable to expect cuts had to be made to fit Fermi into a notebook form factor, but given how underwhelming the performance of the desktop GTX 465 that the GTX 480M borrows its hardware from is, one can begin to become genuinely concerned about NVIDIA cutting too deep to get the GTX 480M to fit into its 100-watt TDP. Both ATI's Radeon HD 5830 and NVIDIA's GeForce GTX 465 have proven that it's possible to hit a wall of diminishing returns when harvesting high-end GPU die; both of these cards are barely faster than their substantially smaller predecessors.
Still, it's impressive Fermi made it into a notebook form factor at all. 352 of NVIDIA's CUDA cores are nothing to sneeze at, and a 256-bit memory interface connected to 2.4 GHz GDDR5 still produces a healthy 76.8GB/sec of bandwidth. The GeForce GTX 480M also brings to the table full DirectX 11 support along with all of NVIDIA's usual trimmings: CUDA, PhysX, and 3D Vision. With Eyefinity largely out of the equation in notebooks, the Mobility Radeon HD 5870 can certianly begin to feel feature light compared to NVIDIA's hardware.
So that's all well and good, but how does the GeForce GTX 480M actually fare in practice?