Second generation GPU client on ATI hardware (GPU2) FAQ

Table of Contents

General instructions

This web page will serve as the FAQ and Release Notes for this new client, and we will update this page as more information becomes available.

The FAH GPU Client installer should do everything one needs. It installs the new v6.x SysTray style client, as well as DLL files used by this new client. Download the client from the High Performance Client Download Page for folding experts. If you need a guide to help you get thru the installation process, it can be found here.

Basic Requirements:

• 2xxx/3xxx/4xxx ATI Video Card, or newer
• ATI Driver v8.1+, v8.3 or newer recommended, up to v9.2 (v9.3 not supported yet) (do not use OEM drivers)
• AGP GPU aperture size in the BIOS must be set to 128 MB or larger
• Microsoft .NET Framework 2.0, with updates recommended
• Windows operating system, XP or newer

This is a beta release and we expect there will be bugs, flaws, problems, etc. To minimize problems, we have been testing the client and cores extensively in house and they run well there. However, it's our experience that running in the controlled setup in our lab and running "out in the wild" are very different situations.

As in the use of any beta software, please make sure to back up your hard drive, and do not run this client on any machine which cannot tolerate even the slightest instability or problems.

Issues specific to GPU2/ATI

I'm having problems with Vista, any ideas?

We have seen reports that the GPU client only works well in Vista when running in "XP Compatibility Mode" or to "run as Admin." We suggest trying this out if you are having problems with the ATI client in Vista. We are investigating work arounds.

Does the new GPU client run the same WUs?

No, this new second generation GPU client will run a different set of WUs specially constructed for the Fahcore_11.exe functionality. Fahcore_11 will not run with the first generation GPU client, and Fahcore_10 will not run with this new client.

What about multi-gpu support and the -gpu switch?

Running multiple GPU2 clients, one client each on multiple GPU cards, is supported through the -gpu x command line switch. The setup is similar to running multiple SysTray CPU clients.

• Copy your \Application Data\Folding@home-gpu folder to a new folder \Folding@home-gpu2 (\AppData\Roaming\Folding@home-gpu in Vista)
• Create a new shortcut for the first client, and be sure to use the correct Target: and Start In: information. Note that one has to be very careful with shortcuts, and in particular, make sure that the "Start in:" field is set correctly. If you are having problems with automatic core upgrades, it is likely that your short cut is not set up correctly.
• Edit the shortcut properties to add the -gpu 0 switch to the end of the Target: field.
• Create a new shortcut for the second client, and be sure to use the correct Target: and Start In: information.
• Edit the shortcut properties to add the -gpu 1 switch to the end of the Target: field.

Except for the different -gpu x switch, the Target: field in both shortcuts will point to the same FAH executable. The Start In: field for each client will point to the two different \Apps Data\FAH folders. The Target: and Start In: fields for a SysTray client are explained in more detail below.

The display must be active on the GPU card you plan to use, and –gpu 0 will select the first board, –gpu 1 will select the second board, -gpu 2 the third board, and so-on. You will need to disable crossfire for multiple boards to be detected. You will also need to use different Machine IDs for each client. Currently, only one client is supported on a 3850X2 or 3870X2.

More details ca be found in the Windows GPU Guide.

What's different between the old and the new FAH GPU client?

Scientifically, the new client introduces several new advances which makes it much more useful. It matches the advanced water models in the PS3 client and adds a new one (which will likely appear in a future PS3 client). These more advanced water models make this new GPU client very useful to us.

There are also many changes under the hood. The previous generation client proved to be problematic due to GPU-specific issues and we've fixed all of them (as far as we can tell) in this second generation client. An important part of these fixes is using ATI's CAL instead of DirectX (the previous generation GPU client highlighted several issues with using DirectX). A major upside to using CAL is that DirectX context switches no longer affect the client. Actions such as fast-user switching, or locking your computer have no effect on GPU processing. Remote desktop does still affect the GPU client and will cause the FahCore to fail when a connection is initiated. VNC does not have the same problem and can be used as an alternative.

Initially, this new client will be a SysTray style client only. A console version may follow later.

Can I still use my GPU when the client is running?

Yes. Unlike the original GPU client, which interfered with many operations that used the GPU, the new CAL-based client does not. Playing videos and playing games either have no effect on the action of the GPU client other than a slow-down in processing, or cause a temporary suspension of folding. The new client will automatically back off whenever an application requests exclusive DirectX mode, although it is not reported in the client logfile. DirectX programs that do not request exclusive mode will cause the GPU client to slow down, and may in some instances have a detrimental effect on application performance. Full screen video is unaffected by the GPU client.

What hardware does the new client/core support?

The client runs on all hardware supported by the AMD Compute Abstraction Layer (CAL), i.e. R6xx hardware, Radeon 2400 and above. The 3870 X2 has not been tested with both cores active, but running on 1 core does currently work.

What OSs does the new client/core support?

The client runs on Windows XP 32-bit/64-bit and Vista 32-bit/64-bit. Windows XP should have SP2 installed. XP and Vista use different CAL DLLs (see below), but the installer should install the correct ones for you.

What about hardware clocks?

On 3xxx hardware or newer, 3D clocks will be set automatically when FAH runs and you can adjust the clocks rates for core and memory in Catalyst Control Center in the Overdrive panel. Note that stable clocks for graphics may not imply stable clocks for Folding, overclock at your own risk. On 2xxx hardware, setting to 3D clocks is not reliably automatic, so a third party tool like ATI Tray Tool can be used to adjust clocks. Once again user beware. The recommendation is to leave the settings alone and fold at the clocks set by the driver.

How about AGP vs PCIe slots?

Performance of the GPU client is best with the board in a PCIe x16 slot. An x8 or x4 slot will cause some degradation in performance as the communication path between the CPU and GPU will be slower. AGP hardware is supported, but overall performance will be lower than PCIe boards because of a slower CPU to GPU connection. PCIe v2.0 is only marginally faster than PCIe.

The client displays an error saying that I do not have a supported GPU, but I do!!!

When the client displays the error At present, only ATI Radeon HD 2xxx/3xxx/4xxx and ATI FireGL Vx6xx GPUs are supported the client did not recognize your GPU card. If you have a supported 2xxx/3xxx/4xxx model GPU, this error is most likely caused by custom device drivers that do not work with the GPU2 client. Some OEM and some laptop vendors modify the Catalyst drivers that ship with their cards. Download and install the latest ATI Catalyst drivers.

At present, the primary video device must also be a supported 2xxx/3xxx/4xxx model, or you may see this error as well. The error CoreStatus = FFFFFFFF (-1) is also a symptom. Changing the ATI card to be the primary display device will resolve this.

The core can't find the DLL's!

We've been seeing some unusual behavior with virus scanners. We are looking into this. For now, give it a second try and it should work.

A DLL error dialog box is popping up -- what's up with that?

If the DLL error pops up, go to the installed location, C:\Program Files\Folding@home\Folding@home-gpu by default, and make sure the amdcalcl.dll and amdcalrt.dll ended up there with the FahCore_11.exe file and run the client from that location.

What's with all the new DLL's anyway?

We're using a new system (CAL) which uses a few DLL's. We are looking into the possibility of statically linking the whole thing to avoid DLL issues, but for now we've got DLL's.

Who did all of this anyway?

In alphabetical order:

• Adam Beberg (Pande Lab): client modifications, GPU's APIs under the hood
• Dan Ensign (Pande Lab): server setup, science, testing
• Mark Friedrichs (Pande Lab, Simbios): core science code updates, testing
• Mike Houston (AMD): testing, problem solving, GPU tuning
• Vijay Pande (Pande Lab): Project management, fitting square pegs through round holes, etc
• We would also like to thank the Folding@home Community Forum moderators for their help with this FAQ and some early beta testing of the software.

For More Information

• ATI Folding Page
• ATI Stream Computing FAQ
• FAH FAQ
• Folding Support Forum

Last Updated on April 19, 2009, at 01:18 PM