I just got an Athlon II 620, and when running 4 instances of prpnet,
I get about 1.1 ms per bit at the 48k FFT range, i.e. 2^501000, at stock speed of 2.6 Ghz.

Since this chip is 4 core for $99, I figure people would want to know.
I am using a GIGABYTE GA-M61PME-S2P motherboard and DDR2
single channel 800mhz memory, running the latest Ubuntu.

Steven Harvey



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How does this architecture and/or phenom II compare to intel core i5 for LLR crunching?

Thanks

From looking at the mersenne benchmarks, Athlon II is about the same as Phenom II. & they are about 10% slower than i5 on large FFTs (1024k and up). However, I have found my Athlon II to be about 2/3 the speed of my q6600 on 48k and 64k FFTs. 64k FFT = ~1.8ms per iteration.

Steven Harvey


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I got my stuff on newegg. I have found that their prices are usually about as low as anyone elses, and also that their customer service is superior. The motherboard I got has two memory slots.
I am using just one, so its single channel. Presumeably dual mode would be faster, but in my experience, single or dual doesn't make much difference to LLR. I have DDR2, & perhaps DDR3 might be faster, but again, I doubt it, because LLR seems to mostly just use the cache on chip.
I opine that the reason the chip is slower than intels may be because the 512k cache per core is just insufficient.
I have also found in the past that memory speed doesn't seem to make much difference to LLR, so at present I just use DDR2 800.
I am running it strictly as a number cruncher, with just the motherboard, chip, memory, and a flashdrive with linux installed. This minimal configuration running four instances of LLR uses 125 watts, so it's not a winner on power consumption either.
I think the best bang for the buck currently would be an intel q8200 or q8400, and a cheap motherboard like the GIGABYTE GA-G31M-ES2L which costs $53 at newegg right now. I like Gigabyte boards because they have solidstate capacitors. and I have two of this particular one.

Hope this helps. Happy numbercrunching.

Steven


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Hey Steve,
Did that 620 come with the cool HSF with heatpipes? The one that came with my Phenom II does and looks like it'll do fine. What difference is there with no L3 cache ? { if that makes a big difference}
I was looking at the Athlon II 's also but opted for the Phenom II. Thanks, Jack

It comes with a very generic small HSF, no heatpipes. I don't have a Phenom to compare whether the L3 cache makes a difference. Why don't you run some tests and report your results?

I have updated the bios and am now running in console mode without a Xserver and am getting about 1.35ms per iteration on a 64k fft, at 2.6 Ghz, which is much better, but still not a good as a core 2, probably about 10% slower.

We should come up with some numbers in benchmarking stock speed processors.

1. we would need a test standard
2. a graph or table would need to be organized taking in account 32-bit/64-bit OS/application ect.


More specifically I would be interested in some 32 bit LLR benchmarks. I can't use the stats in primegrid due to overclocking, and not being able to determine other variables.

Thoughts?
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