I think the major reason for the change is to retain members. Too many people run the grid for a few days, see the 100% in task manager, and decide it's more than their boxen can take. It's a reasonable view. There are risks associated with crunching, and it's important not to be blind to them.

WCG have decided that the increased active membership offsets the loss of direct CPU usage.

Still, I would like to know how the mechanism works, so I can advise people properly on making the change to multiple computers.

For the die-hard crunchers, my advice (as ever) is "migrate to BOINC".

I think the explanation about slow-downs is slightly disingenuous. Most actual delays are caused by paging. Of the tiny remainder, some delays are caused by conflicts with certain programs that occassionally run low priority threads in the background (AutoCAD for example) - and some delays remain unexplained. Throttling may help some of these situations, but won't help with the paging.

The GUI tool that we have made available is for the convenience of non-techies. It provides a very straightforward way for people to adjust their CPU utilization. The primary use is to control the CPU temperature. As to impact on the machines, paging is still primary reason.

The way the throttle tool works is simple: it's just sets a registry entry.
Key: HKEY_CURRENT_USER\Software\IBM\World Community Grid
DWORD Value: 'CPU Throttle'
Value: anywhere from 25 - 100.

This allows several benefits:

• You can make a .reg file that you can easily import to many machines without having to go to each one physically.
  
• Allows you to dynamically adjust the throttle in response to exceeding temperature thresholds. e.g. Many CPU/Fan monitors allow you to call programs when certain conditions arise. You could write a simple script/program that lowers the CPU usage if the temperature exceeds 60C, and raise it when the temp drops below 50C.
  

You should also be aware that not just HPF2 is affected by this new default. All the UD apps have been retrofitted with this new setup.

If you happened to use the old environment variable method, that value is copied to the registry the first time it's queried.

I can't help noticing this is an HKCU value, so must be set for each user. I'm assuming setting the value in HKLM won't override the value (or be noticed at all?)

Hello madmac,
Whenever a new project starts, it is selected for everybody by default. Just go to My Grid - My Projects and uncheck the box for HPF2.

Lawrence

A few more points regarding the new default throttle setting.

1. We want to be as unobtrusive as we can on our members machines, and especially the less techy users who might have a difficult time trying to go through the steps of adjusting the throttle or any other settings.

2. This new default setting may convince some corporations and school systems to join in with a large number of devices, who might otherwise be on the fence, trying to decide whether to deploy agents on their organization's machines. It may also ease any concerns PC manufacturers might have and make them more likely to preload the agent or a link to it. We will see how this goes over time.

3. For those using custom scripted installs, the throttle tool can be run with a parameter to make the setting without using a gui. See the help link within the throttle. For example, to set the throttle to 80%, one would use the tool in this manner from a command line:

WCGridMaxCPU.exe -t 80