Welcome Back SpeedRaider!

[guru]

Watts are watts! What you are talking about is watts/work unit or efficiency. Yes the 4770K is more efficient than the 2700K but not by a lot.

Getting back to the two 2700K vs single 4770K output. That is 258 watts vs 142 watts. With power at $.064 a KW here that comes to $63.91 a year extra in power but it also outputs more units. The added bonus is the two 2700K's will crush the 4770k in other work. SOB is one of the few workloads that has a big advantage on the 4th generation core processors.

[pinhodecarlos]

Watts are watts! What you are talking about is watts/work unit or efficiency. Yes the 4770K is more efficient than the 2700K but not by a lot.

Efficiency is one thing, specific energy consumption is another thing.
When you are on a site you look at a efficiency of a boiler but for a production line you look at the specific energy consumption. The latter is what you need to be use to compare your computers. Your computer is a production line where you feed with energy (electricity) and it produces X candidates per day. The efficiency is measured on the power supply (consumed/feed)_energy.

Also that unit KW doesn't exist because the K (capitalize letter) is Kelvin, for absolute temperature, what you mean is kW, where k is a SI prefix and it is named kilo. Second you pay energy (kWh) not power (kW). Third you need to consider the overall investment for each case, you can't only compare the energy you pay, you need to determine the ROI (return of the investment). This is what you do in the real world.

[tim]

Sounds like you two guys know a lot more about this than me. So, if I'm following, I'd need to look at how much work gets done per kilowatt/hour used. Or kW/h if I have the nomenclature right. And for me the initial cost of the system does have a bearing. Looking at cpuboss, the 2700k is behind the 4770k, but not by a lot. 2700k vs. 4770k: AVX vs AVX2, DDR3-1333 vs DDR3-1600, $83.22 vs $73.58 annual cost. Clock speed and turbo speed the same, memory cache amounts the same. $400 through amazon vs. $345 at newegg. If I understand right, for SOB I'd want to look for a 4770k?

[guru]

If you are buying new the 4770k or 4690K are good choices. The 4960K should be cheaper with very similar performance. If you shop used and can get a good deal(say half of the price of 4770k) on the 2500k, 2600k or 2700k they will give good results.

I'll be out crabbing tomorrow so no new updates until Sunday.

[pinhodecarlos]

Tim,

There is memory bottleneck issues which means you need to have faster memory and bigger cache. Also you won't take advantage by having HT on the processor so you can rule out i7 and stick with an i5.
Because SOB is running candidates with exponent n=29M, you will see a big degradation in speed when you keep adding instances, this means that you need to understand on your processor if it is better to have one or two or three or four instances running. Example, I have two laptops, one Haswell and one Ivy Bridge, and I only can run on them two instances of prime95 (or LLR) but I am running RPS project with k=5 and n=4.6M. Memory is DDR3 1600 MHz. At this exponent by adding a third instance I can notice memory issues, decrease on overall output.

What people do on Prime95 project (GIMPS) is to only run 2 LL tests (these tests take like 30 days or more, not sure for now) and 2 factoring because it is more efficient to do this on a quad core machine. In guru machines I would run half of the cores with SOB and the other half on dnet...something like that....

At the end if you don't care about the best efficient way to run SOB just run one thread of Prime95 per psychical core. If you care for now the best overall option, for home users that pay electricity, is the core-i5-4690k with DDR3 at 2400Mhz, taking into consideration that fact that it is needed to make a test on how many cores you should run (for SOB, high exponents to test).

Carlos

[guru]

Tim,

There is memory bottleneck issues which means you need to have faster memory and bigger cache. Also you won't take advantage by having HT on the processor so you can rule out i7 and stick with an i5.

Carlos

Yes you don't need the HT from the i7 but the i7 does have 8mb cache vs the 6mb cache of the i5. That 2mb should make a difference in SOB.

[tim]

Thanks for the advice. I'm not finding refurb i5 4690k. I'll have to look at building. Or get back into it, it's been years. The last one I built was a Athlon xp 3000.
Too bad nobody makes a LGA-1150 dual socket mobo. Or an AM3+ dual. 16 cores on one home machine would be nice.