Posts by Snuggles

1) Message boards : BOINC client : Buyers' Guide to Cheap BOINC Crunchers (Message 14197) Posted 3 Dec 2007 by Snuggles Post: Please read this entire message before posting. Goal: Run BOINC as efficiently as possible to get the most speed for the money - the initial purchase price and the price of ownership, such as power requirements. Post your best criteria to determine the best value of computer parts. My criteria, so far, are CPU wattage and CPU speed per dollar. By CPU speed, I mean the CPU features that are most common to all BOINC projects, not just one CPU feature for one project. When replying, please make your post relevant to the goal I outlined in this post. Your post must help people to make the best purchasing decisions for running BOINC as cheaply as possible. Again, I have no specific BOINC projects in mind. Your post should apply to as many projects as possible (lowest common denomination of features), and apply to as many people as possible, not just techno-geeks with supercomputers in their basements. If you post something technical, make sure it's actionable information for the buyer. If you post an acronym such as FPU, spell it out as FPU (Floating Point Unit) once and explain to the buyer how to look for that feature in a CPU. If you say MHz is misleading, tell us what else we should look for in a CPU that would apply to as many BOINC projects as possible. If you say a bigger cache is better, tell us the best size for the dollar to be affective to as many BOINC projects as possible. Please don't post a negative message without also posting a positive, results-oriented message that's useful for the buyer. I hope this message and the replies to it will encourage the purchase of more computers for running BOINC projects. Thank you.
2) Message boards : BOINC client : Cheap PCs for BOINC (Message 14175) Posted 2 Dec 2007 by Snuggles Post: E4500 2.20 GHz: 65 Watts, which comes out to be 0.0338 GHz per Watt; $125, comes out to be 0.0183 GHz per Dollar. On the other hand, the Q6600 at 2.4 GHz: 95 Watts, comes out to be 0.0252 GHz per Watt; $280, comes out to be 0.0085 per Dollar. The Q6600 basically consists of two E6600s in a single package, so as Les says it can do twice as much work as a dual core processor. If I recall correctly, the E4500 has a small cache and a slower front-side-bus, and half the cores of the Q6600. So in reality it has about a third of the throughput of the Q6600. And you're not taking into account the electrical overhead of the rest of the system it fits in. I purposely left out the electrical overhead of the PC because I can't possibly know what system people will put these CPUs in, but I do know what power the CPU uses, so that's what I talk about. I have now taken into account the combined GHz of the cores of both CPUs (the Core 2 Duo and Core 2 Quad), and the Core 2 Quad gives you more GHz per Watt, but slightly less GHz per Dollar. So it turns out the Core 2 Quad gives you more value, but at a higher initial cost and at higher wattage. So with that, it comes down to a personal choice between the two. Core 2 Duo: 4.4 GHz combined cores: 0.0676 GHz per Watt; 0.0352 GHz per Dollar. Core 2 Quad: 9.6 GHz combined cores 0.1010 GHz per Watt; 0.0342 GHz per Dollar. Why don't you do the calculations for the FSB and cache and compare the two for the dollar amount of each?
3) Message boards : BOINC client : Cheap PCs for BOINC (Message 14168) Posted 30 Nov 2007 by Snuggles Post: the crunching speed is also heavily project dependant. For example, Rosetta doesn't make use of SSE extensions while some projects do, as well as their general FPU and cache dependancies etc. However, if you want to get good performance per watt, i don't think much analysis would be needed to pick out the Q6600 as mentioned. It can also be overclocked, although OCing increases the power consumption (not linearly) and so there is a point where the gains from OCing will be relatively small in comparison to the increased energy needed to run at that speed. Another free option/factor that can make a big difference to the efficiency is undervolting. If you're running a CPU at stock speeds then reducing the voltage of the CPU can reduce it's power requirements massively. I reduced my laptop CPU (1.86GHz Pentium-M (Dothan core)) from 1.325V down to 1.053V using RMClock and the battery lasts around a third longer (while running Rosetta). Crunchers also don't need hard drives - you can net boot, or my preference is to boot from compactflash cards. My media centre boots Windows MCE 2005 from a 2GB CF card - TV is recorded to the server over the network. Other things that help reduce electrical consumption are onboard video, no keyboard/mouse, good airflow (less electrical resistance at lower temperatures), few fans, and not running where air-con is needed! HTH Danny Thank you Danny, for your most relevant message! You've made lots of good points. How can I determine a project's FPU and cache dependancies? You mentioned the Q6600 as having good performance per watt. I did a comparision of the Q6600 with the Core 2 Duo E4500, and the E4500 actually gives you more speed per dollar and per watt. E4500 2.20 GHz: 65 Watts, which comes out to be 0.0338 GHz per Watt; $125, comes out to be 0.0183 GHz per Dollar. On the other hand, the Q6600 at 2.4 GHz: 95 Watts, comes out to be 0.0252 GHz per Watt; $280, comes out to be 0.0085 per Dollar. So with those criteria, it looks like the E4500 gives you more speed per initial dollar investment and for long term power requirements than the Q6600. The whole point of me calculating this and doing CPU comparisons is to give people the information they need in order to build the cheapest possible PC for running BOINC on. So I hope they find this useful. You said crunchers don't need hard drives. Interesting! Did you mention this to point as another way of reducing costs per PC?
4) Message boards : BOINC client : Cheap PCs for BOINC (Message 14135) Posted 27 Nov 2007 by Snuggles Post: I just found the perfect link! It's all about BOINC performance - how to increase it and what hardware features make BOINC crunch faster. BOINC PERFORMANCE FAQ
5) Message boards : BOINC client : Cheap PCs for BOINC (Message 14111) Posted 26 Nov 2007 by Snuggles Post: EDIT: also, you need to take into account the power consumption, not only the computer price. Electricity has to be paid for too. :) My original post was as much about power consumption as it was about CPU speed.
6) Message boards : BOINC client : Cheap PCs for BOINC (Message 14105) Posted 26 Nov 2007 by Snuggles Post: For most BOINC projects an effcient FPU is a prime consideration. If the on-dye cache is large enough to hold the project's working set it can make a huge difference. Number of cycles per instruction. I have a VIA at 800mhz it takes about twice as long to process tasks as my 500mhz PIII did. The CPU may have changed since that one. However they are designed for low heat generation not intensive processing. It is a good processor for surfing the web and embedded devices though. My best computer for crunching is a intel core 2 running at 1.6ghz. It beats out a P4 @ 2.0ghz, a celeron @ 2.8ghz and an AMD X2 @ 1.8ghz. In layman's terms, can you explain how I would go about looking for a CPU with these features? How can I find out if a CPU has an efficient Floating Point Unit? By "on-dye" cache, do you mean the registers, or L1/L2 cache? How big should they be for BOINC? This is where I get a little lost: CPI or Cycles Per Instruction. I found an explanation on Wikipedia.org but could you tell me how I can apply this to BOINC? By the way, I know what you mean when you said your Intel Core 2 1.6 GHz is actually better at crunching BOINC than higher-clocked CPUs. I too have a Pentium 4 at 2.6 GHz and it's actually slower than my laptop with an Intel Core Duo 1.73 GHz. I wish I knew how this is possible. Maybe this thread will help explain that.
7) Message boards : BOINC client : Cheap PCs for BOINC (Message 14100) Posted 25 Nov 2007 by Snuggles Post: Clock speed is not everything in crunching. In fact I would recommend strongly against any of the Via CPUs. They tend to be much slower in BOINC projects than the raw speed would indicate. You indicated that clock speed is not the only factor involved in determining a CPU's ability to crunch BOINC work units. Can you detail what other factors are involved in negating the importance of a CPU's clock speed? Perhaps explaining this would also explain why you believe a VIA CPU is "much slower" than the clock speed indicates. I'm glad you brought this up, because although my post was about finding CPUs with the most MHz per watt, you brought up the point of how the clock speed may not be as important as my post may have suggested. Your post now has me wondering what features of a CPU might make it better suited for crunching BOINC work units, other than raw clock speed.
8) Message boards : BOINC client : Cheap PCs for BOINC (Message 14081) Posted 25 Nov 2007 by Snuggles Post: The purpose of this thread is to discover cheap ways of running BOINC as much as possible. That could mean finding the lowest wattage CPU, or the cheapest PC just for BOINC. A friend sent me this link to a $200 desktop with a VIA C7-D 1.5 GHz CPU, which uses 12 watts! $200 PC Now that's computing on the cheap! That's 128 MHz/watt. Very good. Here's how to calculate how many MHz you get per watt of power: [CPU SPEED IN GHZ] x 1024 / watts = MHz per watt If the CPU is only in MHz, just do this: MHz/Watts = MHz per watt. Obviously the more MHz per watt, the better the value (more speed for less money per CPU). Don't know the wattage of your CPU? Check out this chart: CPU Wattage

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