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Old 2015-08-02, 00:23   #12
wildrabbitt
 
Jul 2014

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Thanks for the answers by the way.

When I run 6 70 million + exponent Mersenne tests each takes about 3 months.

About the memory.

Can someone answer : Why does a LL test need more than 2GB DDR3 ?

I don't want to waste any money at all by buying unnecessary RAM.

Last fiddled with by wildrabbitt on 2015-08-02 at 00:23
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Old 2015-08-02, 00:38   #13
VBCurtis
 
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Quote:
Originally Posted by wildrabbitt View Post
Thanks for the answers by the way.

When I run 6 70 million + exponent Mersenne tests each takes about 3 months.

About the memory.

Can someone answer : Why does a LL test need more than 2GB DDR3 ?

I don't want to waste any money at all by buying unnecessary RAM.
It doesn't. Henryzz told you so, above. But 1gb sticks aren't meaningfully cheaper than 2gb sticks, and you need a pair.
Edit- You can see how much memory a LL test needs, on the machine you have now. Have a look in the task manager, or top (linux).

You didn't answer about the time for 3 concurrent tests rather than 6. Iteration times are all you need, rather than a full test!

Last fiddled with by VBCurtis on 2015-08-02 at 00:47
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Old 2015-08-02, 00:41   #14
wildrabbitt
 
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You mean I can't have 1 2GB stick, but I could have 2 1GB sticks? Something about having a pair?
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Old 2015-08-02, 00:51   #15
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Quote:
Originally Posted by wildrabbitt View Post
You mean I can't have 1 2GB stick, but I could have 2 1GB sticks? Something about having a pair?
LL tests are memory-bandwidth constrained. A machine will boot with a single stick, but a second LL test will saturate the single memory channel, such that it won't run as fast as one test runs alone. You need two channels (= two sticks), unless you really don't care how much work you get done and just want to say you run Prime95. Even with two channels, 4 tests will saturate the memory- 3 tests with one core idle will run nearly as fast as 4 tests. This effect depends on memory speed and CPU speed- try reading some threads here in the forum. The effect is well-documented.
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Old 2015-08-02, 02:28   #16
retina
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Quote:
Originally Posted by wildrabbitt View Post
I run 6 LL tests at a time on my FX6300's.
The reason people are telling you that you should consider only running 3 tests is that the AMD CPUs share one FPU/SSE unit between each two cores. So running 6 tests is probably going to be overall slower than running 3 tests and then running another 3 tests when the first 3 are finished. Check your iteration times and then use a calculator to see the difference.

But even after all the twiddling and finding the sweet spot for the AMD system, you would still be better off, speed and electrically wise, with an Intel chip.
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Old 2015-08-02, 03:12   #17
Batalov
 
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(It's been a while since I looked at GBP / USD; I was still thinking about a factor of ~2; but it is only 1.56 now.
Because of that £100 won't get you a quad-core, but only a i3-4360 .. 4370 ? Still worth extending another £30 to reach for a i5-4570. Or only £15 for a 4430.)

Like Curtis said, even a 4360 will run circles around the FX6300.
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Old 2015-08-02, 11:39   #18
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Quote:
Originally Posted by Batalov View Post
(It's been a while since I looked at GBP / USD; I was still thinking about a factor of ~2; but it is only 1.56 now.
Because of that £100 won't get you a quad-core, but only a i3-4360 .. 4370 ? Still worth extending another £30 to reach for a i5-4570. Or only £15 for a 4430.)

Like Curtis said, even a 4360 will run circles around the FX6300.
As someone who runs an FX-8350, I strongly recommend that you listen to the Intel advice given above. Unless electricity is free for you, the minimal i5 you can get will pay for the difference in cost fairly quickly with power savings. It will also do more work.

Where RAM is concerned, trying to run Windows 7 or higher on 2, or even 4 GB is likely to be counter productive. Too much of the system will inhabit the paging file, and it will waste time thrashing the HDD.
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Old 2015-08-02, 14:13   #19
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Why running Windows?
Even with small knowledge of Linux you can install Linux, minimal distro: and run it. In any case use two channel mode ( two sticks of same size) it is faster ( on AMD and on Intel)
Good luck!
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Old 2015-08-03, 09:48   #20
wildrabbitt
 
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I never said I was running windows.

Someone on this thread assumed I was. Apparently now it's a fact.

I run ubuntu 10 for all my machines excpect two.

Thanks anyway for the advice which might have been useful if I really was running windows.

Two questions have arisen since the other day.

1. A £120 intel CPU and 4GB of ram running tiny core linux of a flash drive. Bad idea?

2. Why does P95 use floating point numbers for doing a test which only involves integers?
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Old 2015-08-03, 09:54   #21
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Quote:
Originally Posted by wildrabbitt View Post
1. A £120 intel CPU and 4GB of ram running tiny core linux of a flash drive. Bad idea?
Relying on a flash drive was okay for me, except when there was repeated power cuts. I would recommend using a cheap 3.5 inch sata-III hard disk.

Last fiddled with by paulunderwood on 2015-08-03 at 10:02
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Old 2015-08-03, 10:09   #22
wildrabbitt
 
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The trouble is all Sata HD's these days are huge memory wise. The only cheap ones I can find are second hand. That's okay though I
guess.
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