Posts by miw

1) Message boards : Number crunching : We need a new forum (Message 29010)
Posted 7 Oct 2006 by Profile miw
Post:
I think Dr. Anderson was just asking an interview question. It may not be BOINC's most pressing problem, but it is one that would be pretty knotty to solve and you need to know how Boinc works in order to be able to propose any kind of reasonable solution.

Back when I was hiring new engineers I had a few questions like that to really see what the applicants were made of. e.g. "Take this whiteboard pen and design me a divide-by-three counter using logic elements available in 74xxx-series TTL chips."

You could learn more about an engineer by watching them work on it than you could by reading 100 pages of CV.

2) Message boards : Number crunching : "which AM2 mobo's are good for overclocking?" (Message 26223)
Posted 7 Sep 2006 by Profile miw
Post:
No. My goal is to get the temp down to about 56 degrees even when the aircon is off and I am overclocking by 10%. Turning the fan over basically put the temp sensor on exit rather than on entrance, which improves the control laws of the system. seems silly to have a fan that can to over 5000RPM idling along at 3200 RPM when the CPU is cooking at 60+ degrees. When I get to a decent shop I am going to get a Scythe Ninja cooler and give that a try. Nett effect of turning the fan over was an increase from 3300RPM to about 4000RPM when the aircon is off. (and a 2-3 degree temperature drop on the CPU.)

Could you cut the thermal resistor out off and connect the wires together directly? I think that'd make the fan run at 100% so you could control it using speedfan or something similar on the motherboard.


yes. Maybe. Looked very fiddly to do and I haven't been brave enough to try as yet. :-) But "disable the temp control to 100% all the time on the fan" would be the result I am looking for.

3) Message boards : Number crunching : My rant: Why you should care about the credit-system (Message 26187)
Posted 6 Sep 2006 by Profile miw
Post:

Yeah I too think it has improved recently. The major 4 projects you mentioned have now switched to credit/WU which improves teh situation quite a bit. With the recent reduction on Einstein the credit/hr between the different projects has also approximated. However after a brief look on the results at Einstein it seems to me they still grant about 20% more credit/hour than Rosetta for example.


Yup. Bang on. My main cruncher's recent credit/hr (Athlon 64 X2 4800+)
Rosetta: 32.7
Seti: 34.4 (Chicken's optimised app)
Climate Prediction: 33.9
Einstein: 47.3

But: Climateprediction just upped credit/trickle by 14.3% today.
(226.8/trickle to 259.2/trickle)
Einstein flys very fast on CPUs with SSE2 and SSE3 but not so much on
slower CPUs, so it may not be so much out of whack on other platforms.

4) Message boards : Number crunching : "which AM2 mobo's are good for overclocking?" (Message 26186)
Posted 6 Sep 2006 by Profile miw
Post:

I managed to fix this somewhat by turning the fan over so it sucks air through the heatsink rather than blowing on it. This way, the air has already been used to cool the CPU and is a few degrees hotter. What's more, as the CPU heats up so does the air (somewhat). Using this technique, I managed to get a good 2 degrees cooler than with the fan the other way, and a good 5 degrees better than any of the after market HSFs that I tried.

Ouch that sounds weird, but if it does what you want so be it. It seems to me your goal is to get the temps down no matter what. My goal is more to keep the temps in line even if I overclock like hell. In that regard I am very satisfied with ARCTIC COOLING Freezer 64 Pro, which is quite inexpensive as well. It's quite big though.


No. My goal is to get the temp down to about 56 degrees even when the aircon is off and I am overclocking by 10%. Turning the fan over basically put the temp sensor on exit rather than on entrance, which improves the control laws of the system. seems silly to have a fan that can to over 5000RPM idling along at 3200 RPM when the CPU is cooking at 60+ degrees. When I get to a decent shop I am going to get a Scythe Ninja cooler and give that a try. Nett effect of turning the fan over was an increase from 3300RPM to about 4000RPM when the aircon is off. (and a 2-3 degree temperature drop on the CPU.)

5) Message boards : Number crunching : Putting a Bell on the Cat (Message 26163)
Posted 6 Sep 2006 by Profile miw
Post:
A few people have mentioned that they'd like us to have an Avatar that makes us obvious. I've been told to ask for your help. Like the mice in the story, please offer suggestions. If you're artistic, feel free to share your vision. The goal is to draw attention to the phrase under our name. To prove that we're not normal users. Keep in mind the ideas need to be appropriate for the board. Creative and stunning is good. Something more practical than giving a Circle K brand to a relative moving onto a farm. And sending them a pic of The Circle K Boneless Chicken Ranch.

Let's see your ideas on how to draw attention to our title. Forcing people to learn Latin is probably out.


Well, at least get the Latin right. That should be "Moderato ergo sum." Now write 100 times, "Romanes Eunt Domus" :-)

--miw
6) Message boards : Number crunching : My rant: Why you should care about the credit-system (Message 26162)
Posted 6 Sep 2006 by Profile miw
Post:
Good Article, but there is really nothing anybody can do about the shambles the Credit System is in. As long as new projects are allowed to come on-line allowing almost unlimited Credit to the participants then the Credit System is nothing but a farce...IMO

You can go to almost any of the newer alpha projects and a lot of people are getting 100-200 or even more Credits per hour by using the Optimized Clients which do nothing but increase their Credits & inflate their ego's ...


Actually I think the credit system has improved quite a bit lately, at least in the projects I particiapate in. (SETI, Einstein, Rosetta, CPDN). the only caveat is that I use an optimised client on SETI, which merely seems to bring Seti into line with the others, but credit/hr is now pretty flat (within 20-25% anyway) across all 4 projects. Only 6 weeks ago I was getting at least double, maybe triple the credits per hour of all the others on Einstein.

So things aren't perfect, but they seem to be improving.....

I also think the article pretty-much gets it. If you want people to crunch your project, you can expect them to give up money, time, sleep, food, sex and grades for you, but don't take away their RAC.

--miw
7) Message boards : Number crunching : "which AM2 mobo's are good for overclocking?" (Message 26161)
Posted 6 Sep 2006 by Profile miw
Post:
I don't know about the X2 3800, but I have Socket 939 4400 and 4800 and they both come with an excellent HSF (Heatsink-fan] assembly (it's a heatpipe design with a very powerful fan). I tries a few whizzbang-looking coolers to see if I could get better cooling out of them, and the stock HSF beat them every time. I'm sure there are coolers out there that are better, but you would need to go right to the high end.

The only grumble I have about the stock HSF is that it is temperature-controlled. That is, although the fan can spin up to about 5115RPM, it will only do that when the air temp in the case is up to about 45 degrees or more. By this time, if you are overclocked, your CPU is labouring along at about 63 degrees. I had to blow a hairdryer at the air intake port to get full speed out of the CPU fan.

Since I prefer to have the fan trying to run at full speed and then slow it down with speedfan or even the Q-fan option on ASUS motherboards, this isn't what I wanted. The Fan speed as it is depends on the temp of the case air rather than the temp of the CPU.

I managed to fix this somewhat by turning the fan over so it sucks air through the heatsink rather than blowing on it. This way, the air has already been used to cool the CPU and is a few degrees hotter. What's more, as the CPU heats up so does the air (somewhat). Using this technique, I managed to get a good 2 degrees cooler than with the fan the other way, and a good 5 degrees better than any of the after market HSFs that I tried.

Be aware that many/most motherboards are designed with the assumption that there is a CPU fan blowing air down through a heatsink and out across the capacitors, which also need cooling. It is not a worry for me, because the caps are sitting right next to a big 120mm case fan that is sucking a lot of air across them anyway. You should think about this though. If you reverse the CPU fan you probably reduce the rate of airflow across the capacitors if that is the only thing stirring the air.

Replacing the heat-conductive pad on the cooler with well-spread (i.e. *very* thinly spread) thermal paste seems to help a bt as well, but I have not quantified it.

Bottom line: I would not get an after-market HSF for an Athlon 64 X2 unless I found I really needed it, and then I would go for a very high-end one because the stock HSF is really pretty good.


[.....]
Stock cooling solution is guaranteed for 3 years on the boxed products. If the CPU or cooling solution stops working, you send it back to AMD and it's replaced for the cost of shipping from you to AMD... If you don't use a stock cooling solution, you're essentially voiding your warranty, but of course it's possibly not easy to prove that - but you may need to send in the heatsink/fan and if it looks like you haven't used the one supplied by AMD, they may refuse to replace it for you...

If you're going to overclock, then you may need to go to a different colling solution - and then you definitely have no right to warranty on the processor anyways... ;-) [Again, it depends on what tests are done to verify the claim here, it may not be easy to prove whether a processor was run at a higher clock-speed than it was intended for...]
[..]
--
Mats

8) Message boards : Number crunching : credit/hour how much is possible?? (Message 26066)
Posted 5 Sep 2006 by Profile miw
Post:
AMD Athlon 64 X2 4800, O/C to 2.58GHz (7.5% O/C)
2GB Ram (clocked at CL2.5)
Windows XP
32.69 Credits/Hr (Most recent 10 results)
hostid=288946

AMD Athlon 64 X2 4400, Stock Clock (2.2GHz)
1GB RAM (forget what type, think it's CL3)
Linux (SUSE 10.1 SMP)
28.92 Credits/Hr (most recent 12 results)
hostid=288952

--miw


That gives you a result of 6.35 (2.58GHz) and 6.57 (2.2GHz) credits per core per GHz.

--
Mats


Yup. I noticed that as well. one of these days when I get back home to the farm, I'll have a closer look at this. Since the 4400 and 4800 have the same L2 cache (1M/core) I sort of expected to get credit/core/GHz about the same for each. But notice that one box is under Linux and the other is under XP. The XP box does some other tasks such as virus scans and backups on a daily basis which may influence things. Memory timings may also have an impact here.

I'll also have a look at this from a SETI and Einstein point of view....

--miw
9) Message boards : Number crunching : credit/hour how much is possible?? (Message 25997)
Posted 4 Sep 2006 by Profile miw
Post:
AMD Athlon 64 X2 4800, O/C to 2.58GHz (7.5% O/C)
2GB Ram (clocked at CL2.5)
Windows XP
32.69 Credits/Hr (Most recent 10 results)
hostid=288946

AMD Athlon 64 X2 4400, Stock Clock (2.2GHz)
1GB RAM (forget what type, think it's CL3)
Linux (SUSE 10.1 SMP)
28.92 Credits/Hr (most recent 12 results)
hostid=288952

--miw






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