New GPU3 project for Fermi: the serious work begins

By , the in Folding@Home Project - 1 Comment
Yu-Shan Lin continues to fuel the GPU3 client with new projects, and has just added her latest: p6811. This is only available to clients running -advmethods, but marks a turning point for what we can expect from GPU client work units.

This project constitutes the first phase of a study on the prion protein monomer. Prion is a proteinaceous infectious particle that is responsible for prion diseases such as scrapie in sheep, Bovine spongiform encephalopathy (BSE) in cattle and Creutzfeldt-Jakob disease (CJD) in humans. These simulations are the Pande Group's first attempt to sample the configurations of the peptide and the results will be used to build Markov states for further sampling.

The project is distributed from the server at 171.64.65.64 and has 2150 atoms, making it the biggest system yet released for the GPU client. The WU is worth 7202 points, and with a preferred deadline of 13 days and a final deadline of 18 days.

As a result of the number of atoms in these units, their behaviour may be different to what is expected. The extra size means that they work newer GPUs much harder than before, and there have been reports of previously stable cards overheating, so watch your temperatures carefully. On "lower-end" Fermi cards (which for the purposes of this simulation means anything less than a GTX460), this unit will saturate the GPU and may lead to a significant loss of performance.

Tobit on the official forums has run performance tests for the most common Fermi-based cards, and his results are thus:

  • GTX480 (700 core/1400 shaders): approximately 14,142 PPD
  • GTX470 (770 core/1540 shaders): about 14 500 PPD (overclocking is important here as it compensates for the loss of some shaders).
  • GTX460 (675 core/1350 shaders): about 8550 PPD (9371 PPD on Tobit's card, but he did not specify the frequency)
  • GTS450 (850 core/1900 shaders): about 6914 PPD

As you can see, the cards with fewer shaders perform significantly less well than their more powerful brothers, this was not shown previously as other units do not saturate the cards so much. Only the most powerful cards show little performance loss (the GTX470's reduced number of shaders compensated for by its higher clock speed).

Sources: Project Description and the Official Forum