[QUOTE=TheJudger;352851]Please ignore voltage and power consumption, I'm currently running 4000MHz at 1250mV, 1200mV isn't stable for Linpack.[/QUOTE]

Oliver... just curious what memory are you using? With DDR3 2000, my setup is v28.1 stable at 4000MHz / 1250mV, same as yours. If I clock at 4200MHz, even 1265mV gave a BSOD twice a day (and at 1275mV, temps were > 80 degrees, so I did only limited testing).

If we use faster memory to relieve the memory bottleneck, the CPU may also be stressed more and in turn that may affect stability again.

If you're having problems with the memory, look into increasing the memory controller's juice. For Ivy Bridge, anyway, that's the VCCSA, mostly, and also the VCCIO. Look them up for your particular hardware, first, as it's been known that there is a fine line.

I think I finally got my system stable with a (not so recommended) VCCSA=1.22v, and all 2400MHz XMP specs intact (10-12-12-31-2T), + CPU Freq 4200 + air cooling (CMaster TPC 612). But this is probably still not over.

[url=http://wimages.vr-zone.net/2013/09/P1100465-665x498.jpg]Look[/url] what's running on a Haswell-E prototype! :smile: No idea what version, though. Probably not 28.1.

I have a Haswell (i7-4770 CPU @ 3.40GHz, hyperthreading enabled), but only 1600 MHz memory. I am considering running 28.1.

I realize I haven't got the memory bandwidth to even fully utilize the 4 cores. I've tried setting NumCPUs=3 in prime.txt, but mprime always queues work and runs 4 processes. Is there a proper way to get mprime to only use 3 cores? If I can keep a core free I'll turn off hyperthreading.

[QUOTE=Ken_g6;352925][URL="http://wimages.vr-zone.net/2013/09/P1100465-665x498.jpg"]Look[/URL] what's running on a Haswell-E prototype! :smile: No idea what version, though. Probably not 28.1.[/QUOTE]
27.9

[QUOTE=Mark Rose;352926]I have a Haswell (i7-4770 CPU @ 3.40GHz, hyperthreading enabled), but only 1600 MHz memory. I am considering running 28.1.

I realize I haven't got the memory bandwidth to even fully utilize the 4 cores. I've tried setting NumCPUs=3 in prime.txt, but mprime always queues work and runs 4 processes. Is there a proper way to get mprime to only use 3 cores? If I can keep a core free I'll turn off hyperthreading.[/QUOTE]

Try setting NumWorkers=3? NumCPUs=3 should be in local.txt.

[QUOTE=ewmayer;352864]Do your timings imply that you are able to run v28 stably?[/QUOTE]

Yes, so far no issues. The difference is too big for just 100 or 200MHz difference when you compare 27.9 to 28.1. This system isn't doing some real work, just testing, etc. so far. But my feeling (and the fact, that Linpack still crashes much faster than v28.1 on higher clocks) tells me, that 4000MHz is OK for my system.

[QUOTE=db597;352887]Oliver... just curious what memory are you using? With DDR3 2000, my setup is v28.1 stable at 4000MHz / 1250mV, same as yours. If I clock at 4200MHz, even 1265mV gave a BSOD twice a day (and at 1275mV, temps were > 80 degrees, so I did only limited testing).

If we use faster memory to relieve the memory bottleneck, the CPU may also be stressed more and in turn that may affect stability again.[/QUOTE]

2x 8GiB DDR3-2133 1.5V CL11 (some fancy Corsair memory)

Oliver

[QUOTE=Prime95;352936]Try setting NumWorkers=3? NumCPUs=3 should be in local.txt.[/QUOTE]

Putting NumCPUs in local.txt worked perfectly. Thanks!

I noticed that I only loose 15% performance per core when I go from 3 to 4 cores. So I still get a 13% improvement running four cores with 1600 MHz memory using 27. I'll test with 28 later. Maybe there will be no benefit to the 4th core then.

Okay, so I got a noticeable improvement from 28.1. And I've overclocked my RAM to 2000 MHz (and increased the timings from 9's to 10's) and I seem to be getting near the max output from all four cores now. Awesome.

Damn, this is HOT!
 

I'm upgrading my i7-860 computer by replacing the motherboard, CPU, and memory. The CPU is the Haswell 4670K, memory is DDR3-2400.

I recycled the i7-860 CPU cooler: [url]http://www.newegg.com/Product/Product.aspx?Item=N82E16835103064[/url]

Right now, with CPU at 3.6GHz, voltage at 1.08 (I can't turn off adaptive voltage, so this should mean 1.18V running AVX instructions), and memory at DDR3-2400, I'm getting temps of 90C running prime95 (up to 100C running the small torture test).

Does this sound right?

Tomorrow, I'll try either 1) reapplying the thermal compound, or 2) using the stock CPU cooler, or both to see if temperatures get any better. I had hoped to get this running at least somewhat close to my first Haswell box running at 4.1GHz, 1.2V (adaptive voltage off), DDR3-2400 and temps of around 80C.