Tesla 20-series (Fermi-based) products are designed for high performance scientific and technical GPU computing.
They thus have features over and above our consumer GeForce GTX 470 and 480 (Fermi-based) products such as:
Double precision is 1/2 of single precision for Tesla 20series, whereas double precision is 1/8th of single precision for GeForce GTX 470/480
ECC is available only on Tesla and not on GeForce
Tesla 20series has 2 DMA Engines (copy engines). GeForce has 1 DMA Engine. This means that CUDA applications can overlap computation and communication on Tesla using bidirectional communication over PCIe.
Tesla products have larger memory on board (3GB and 6GB) for computing on large data sets.
Cluster management software is only available and supported on Tesla products
The TCC (Tesla Compute Cluster) driver for Windows is only available on Tesla
OEMs offer integrated workstations and servers with Tesla products only
HPC ISV software is tested, certified, and supported only on Tesla products
Tesla products are built for reliable long running computing applications and undergo intense stress testing and burnin.
Tesla products are manufactured by NVIDIA and come with a 3year warranty
Tesla customers receive enterprise support and have higher priority for CUDA bugs and requests for enhancements
Tesla products have long availability cycles ranging from 18 to 24 months and NVIDIA gives its customers a 6 month EOL notice before discontinuing a Tesla product.