Emphasis on the when available. I normally run with all projects selected and the alternate work box checked (a bit redundant I'll admit when you check all projects). For every HDC WU I get, I get about 8-9 FAAH WU's. FAAH WU's usually take 7-9 hours for my machine to crunch. HDC WU's usually take 1-3 hours. Presuming that there is no bias in the probability of getting HDC vs FAAH WU's (a very safe presumption in my mind), it would seem that the sheer volume of available FAAH WU's far exceeds HDC. I expect that once HPF2 is back online and we have one or two more concurrent projects running, this won't be as much of a possible concern for some folks.

I just tried requesting just HDC WU's thru my BOINC profile setting (HDC only project selected, alternate work box NOT checked) and got this:

9/24/2006 6:27:38 PM|World Community Grid|Message from server: No work could be sent.
9/24/2006 6:27:38 PM|World Community Grid|Message from server: (there was work but it was committed to other platforms)
9/24/2006 6:27:38 PM|World Community Grid|No work from project

These messages simply say to me that the admins need to load a new batch of HDC WU's for BOINC on Windonts.

So for folks who want to emphasize crunching for HDC, if you check only the HDC project, you definitely want to also check the alternate work box unless you prefer to sit idle when you can't get HDC WU's.

Another thing to remember about HDC. The work units are being created by an automatic scanner, which then undergo some local processing and are uploaded to our server. Looking at Statistics - By Project - Help Defeat Cancer, I see that yesterday we processed 18,674 work units using 10 years of CPU time. This is only 10% of the current capacity of the WCG.

So there will always be a shortage of HDC work units. We are processing them as fast as they come in (give or take a few hours). This sort of rapid turn around is very good for scientists experimenting with different ways of preparing tissue samples. Rapid feed back is important in research.

Lawrence