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Old 2017-10-02, 09:10   #1
robert44444uk
 
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Was thinking about my next hardware upgrade. I do want to be able to contribute a lot more to prime gaps so I want to make a significant upgrade.

I am price sensitive, so what would be a good UK solution for a dedicated standalone air-cooled desktop machine that provides optimal electricity consumption, throughput and ease of use?
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Old 2017-10-02, 09:22   #2
pinhodecarlos
 
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Wait for the intel 8th generation to be released this week in UK.
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Old 2017-10-02, 13:26   #3
axn
 
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Possibly AMD Ryzen might be worth having a look at.
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Old 2017-10-02, 13:33   #4
VictordeHolland
 
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You might want to take a look in the "Georges Dream Build" thread:
http://mersenneforum.org/showthread.php?t=20795

Do the Prime Gap searches have high memory bandwidth requirements (like the LL tests on mersennes candidates?) or are they small enough to fit in the cache of modern processors? If you're memory bandwidth bottlenecked then you could go for an quad core i5 (something like a 7400) with dual-channel DDR4-2400 memory. Combined with a efficient power supply and small micro ATX board you can get great performance/value and performance/Watt (see linked thread).

If you're not bandwidth bottlenecked, go for the most cores/fastest your money can buy. Assuming the code uses AVX, then SMT (or HyperThreading as Intel calls it) is pretty useless, so no need to spend the extra money for an i7 to get that.
Or wait a few months for the new Core 8000 series of Intel, with quad-core i3's and hexa-core i5s .
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Old 2017-10-03, 03:38   #5
rudy235
 
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I think this is interesting.


https://www.pcgamesn.com/intel/intel...e-release-date

Intel Coffee Lake - release date, price, specs and performance

Vital stats

Intel Coffee Lake release date
Intel's next desktop gaming CPUs are set to launch October 5, 2017... and we're getting rather excited about them.
Intel Coffee Lake pricing
With the Ryzen competition Intel can't price their own six-core parts much more than the i7 and i5 of the 7th Gen, so prices start at $117 for the quad-core i3 and top out at $359 for the six-core, 12-thread Core i7.
Intel Coffee Lake specifications
There are four six-core chips: two K-series and two 65W. The Core i7 8700K will top out at 4.3GHz, and the i5 8600K at 4.1GHz, all-core Turbo clockspeeds. There's also a pair of four-core i3 chips finishing the lineup.
Intel Coffee Lake performance
The single-core performance of Intel's new Coffee Lake chips ought to make them great gaming CPUs. And when you bring in the prospect of 5GHz+ overclocking that's going to make things tough for AMD's Ryzen.
_______________________________________________

Update September 29, 2017: Somewhat reminiscent of Tom Cruise swiftly dragging and dropping items on the gesture-controlled screen in Minority Report, industry insiders have indicated to Gamers Nexus that Intel have been chopping and changing their product roadmaps near-monthly.

The same industry insiders have indicated early engineering samples for Coffee Lake and 300-series chipsets featured compatibility with 200-series boards, which was later removed to ensure efficient and necessary power delivery for Coffee Lake to run smoothly.

The latest leaked roadmaps from Intel suggest the remaining consumer 300-series chipsets are on their way in Q1 of 2018. The H370, B360, and H310 are mid-range and budget boards, which will grant budget-minded chips, such as the Core i3 8350K, some degree of value not afforded at launch with the exclusive Z370 chipset.

Also indicated in Intel’s plans is the release of power-efficient Coffee Lake desktop processors, with 65W and 35W models possibly arriving in Q1 2018. These will arrive as six, four, and two-core chips.

Pentium and Celeron processors have also not been forgotten, with a pre-new-year release for the four- and two-core Gemini Lake chips.

Last, but definitely not least, Enterprise will have vPro Coffee Lake desktop processors arriving in Q2, with coinciding chipsets, the Q370 and Q360.
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Old 2017-10-03, 04:39   #6
danaj
 
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Antonio was getting a ~30% increase by using 4+4HT vs. 4 cores on his laptop. This seems to act more like "normal" code and not hyper-optimized Prime95 code. That was back in June with slower overall code, so it'd still be worthwhile seeing more recent benchmarks.

AFAIK, there is no AVX being used. There was some initial thought that the compiler would generate something useful, but I don't see that it does anything. The only actual asm is simple 2-instruction snippets for 64-bit mulmod, addmod, and Montgomery multiply.

It doesn't look memory bound to me on normal machines, but that's definitely something worth measuring (how?). I did find it didn't scale very well from 16->32 cores, and 48 was only a minor improvement from 32 (on a 64-proc AWS machine, which introduces some unknowns). This could be memory, cache, or just the way parallelism is set up.

I'm dubious about trying to use Prime95 hardware recommendations because that code acts so differently than many others. Not that the choices would be *bad*, and it's not quite as far off as looking at recommended gaming builds, but neither of those really match the PGS code behavior.


For my use, I don't want to deal with lots of little machines -- all that hardware and maintenance adds up, nor do I want to start hacking tiny systems. I realize some people do this quite successfully and it cuts costs a lot, but I'd prefer off-the-shelf PSUs, cases, etc. rather than racks of hand-cut plexiglass. That said, I thought the 7940X (14/28-core) looked pretty nice although quite pricy.

Do we have any idea of how AMD Ryzen performs on this? The AMD 1950X (16/32-core) also isn't cheap but seems like it'd do well at a lower price vs. Intel.

The i7-8700K also looks interesting if wanting to spend something less stratospheric. 6/12-core, $359 (vs. $1399 for 7940X), 95W (vs. 165W for 7940X), high clock rates, cheaper motherboard, built-in GPU. Dual channel vs. quad channel, and fewer overall cores.
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Old 2017-10-03, 12:22   #7
VictordeHolland
 
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Is there a benchmark/ PGS standard exponent to test? As to give an indication of how various hardware would perform?
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Old 2017-10-03, 16:45   #8
danaj
 
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Quote:
Originally Posted by VictordeHolland View Post
Is there a benchmark/ PGS standard exponent to test? As to give an indication of how various hardware would perform?
We have not chosen anything. Mostly people have reported n/s for current runs on their hardware. The reported n/s typically takes a while to settle down so it takes a couple hours to get something comparable. Sounds like a benchmark mode would be a good addition (pre-chosen n1,n2,res1,res2,m1,m2,numcoprime parameters leaving sb,bs,mem,t to user; ignore or separate report for all startup activity).

The main sieving operation, if I understand correctly, uses a variant of TOeS's cache friendly sieve, similar to primesieve. This uses craptons of memory while running but the access pattern is not terrible and it has good performance at this range compared to others (which was TOeS's design goal, and why primesieve uses three different sieve implementations depending on range).

From what I can see, most all the extended time is in the sieve. There is a search step that is more cpu bound.

51.2 n/s AWS c4.4xlarge, 16 threads, 28GB (30GB of ???)
46.8 n/s i7-6700K 4.2GHz, 8 threads, 13GB (4x8GB DDR4 2800 CL15 rank 2 1.2V)
34.8 n/s i7-4770K 4.3GHz, 8 threads, 13GB (2x8GB DDR3 2133 CL11 rank 2 1.5V)

The AWS machine produced 55.1 n/s when two 8 thread 14GB tasks were run at the same time. The 6700K vs. 4770K numbers above make me wonder if memory bandwidth is making more of a difference. Perhaps I need to do some tests with 1,2,4,6,8 threads on each to see.
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Old 2017-10-03, 17:43   #9
rudy235
 
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I wanted to know if a machine with a fast processor like the new ones coming out intel i7 8700K and 8600K and intended for prime gap searches could use the same motherboard as a Gaming motherboard.for instance an aorus x299

I realize that a board like this is quite a bit more expensive than for instance MSI - Z270-A PRO ATX LGA1151 Motherboard which sells for $ 60~70
I just wanted to know if it is technically possible to have your cake and eat it too.
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Old 2017-10-03, 17:57   #10
pinhodecarlos
 
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Who can beat this energy efficient laptop?

31.0e9 n/s Intel® Core™ i7-3630QM (3.4 GHz), 8 threads, 12GB (Corsair PC3-12800 1600MHz 16GB Vengeance (2x8GB) CL10 SO-DIMM DDR3 ) - drawing 38W.

Last fiddled with by pinhodecarlos on 2017-10-03 at 17:58
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Old 2017-10-03, 18:43   #11
pinhodecarlos
 
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For the new intel generation I would wait a couple of months until the future BIOS upgrade updates the usual issues the cpu might have. Also more chipsets will be available.
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