Oh Brother, What betid to mine Haswell 4770?

[retina]

Originally Posted by petrw1

By putting the HT cores all first will that cause Prime95 to assign the work to the HT cores instead of the Physical cores?

Sorry I can't answer the rest of your questions. But there is a misunderstanding in that question. Each logical core is indistinguishable from the other. One physical execution core with two logical cores feeding it instructions. It makes no difference to the CPU if you use either the left or the right logical instruction generator to feed the execution core.

[Prime95]

Originally Posted by petrw1

[Main thread Sep 30 11:23] Test clocks on logical CPU #1: 214592
[Main thread Sep 30 11:23] Logical CPU 2 clocks: 407000
[Main thread Sep 30 11:23] Logical CPU 3 clocks: 214576
[Main thread Sep 30 11:23] Logical CPU 4 clocks: 214720
[Main thread Sep 30 11:23] Logical CPU 5 clocks: 214576
[Main thread Sep 30 11:23] Logical CPU 6 clocks: 214712
[Main thread Sep 30 11:23] Logical CPU 7 clocks: 214608
[Main thread Sep 30 11:23] Logical CPU 8 clocks: 214856

What a weird set of results you have.

During this test my 100K clock routine took 200K on all logical CPUs!! Unless there is a bug in my code, some other process was running on that core as well (and that process was also CPU bound), or perhaps there is some clock throttling going on.

[petrw1]

Originally Posted by Prime95

What a weird set of results you have.

During this test my 100K clock routine took 200K on all logical CPUs!! Unless there is a bug in my code, some other process was running on that core as well (and that process was also CPU bound), or perhaps there is some clock throttling going on.

Similar odd results on 3/4. But 5-8 look normal. Could clock throttling only affect some cores? Or I guess there could have been something busy only on cores 1-4. Though that is unlikely as this is an office computer used in a clerical role.

Also all workers including 3 and 4 are slow but their timings seemed normal in the test I ran.

[Mark Rose]

What are the CPU core temperatures when you run Prime95 on all cores? It might be a cooling problem causing thermal throttling.

[petrw1]

Originally Posted by Mark Rose

What are the CPU core temperatures when you run Prime95 on all cores? It might be a cooling problem causing thermal throttling.

Good thought. It would be a stock cooler but no overclock.

[Mark Rose]

Originally Posted by petrw1

Good thought. It would be a stock cooler but no overclock.

Then you're almost certainly running into thermal throttling. The stock cooler can't keep up. There's also little point in running more than 3 cores, btw. There isn't enough memory bandwidth to get much if anything out of the 4th core.

[kracker]

Originally Posted by Mark Rose

Then you're almost certainly running into thermal throttling. The stock cooler can't keep up. There's also little point in running more than 3 cores, btw. There isn't enough memory bandwidth to get much if anything out of the 4th core.

You're probably right.
@OP: Check the temperatures with something like SpeedFan(4.50).

[petrw1]

I understand how it could be temp except I would expect to see these effects during a long continuous heavy load.... and possibly gradual.

But rather what I am seeing from the worker windows is drastic immediate changes whenever one of the other workers changed from TF to LL/DC.
This to me is symptomatic of workers sharing physical cores.

Before I looked at the optional parameter AffinityScramble2 I noted the workers are sharing (in order) CPUS 1,2 ; 3,4 ; 5,6 ; 7,8 even though I have the worker windows set as:
CPUs to use (Multi-threading) 1

Then I used DebugAffinityScramble=1 to have Prime95 run a test to determine which CPUs are HT Pairs.

It confirmed the above pairings ... this tells me that even though it is ignoring the "CPUs to Use 1" setting and assigning 2 cores to each worker it appears to be assigning them properly so there should be no sharing of physical cores.

To Mark's comment of not enough Memory Bandwidth to support 4 cores: I found that to be painfully true on my first generation 4-core (Q9550).
But since then every i5 or i7 (Ivy, Sandy, etc.) have shown minimal degradation of throughput even with all 4 cores doing LL.

[Prime95]

Memory bandwidth bottleneck is back big-time with the Haswell -- especially with standard DDR3-1600.

If it is temp related throttling, then it will happen nearly immediately.

[Mark Rose]

Originally Posted by Prime95

Memory bandwidth bottleneck is back big-time with the Haswell -- especially with standard DDR3-1600.

Yep. The machine I'm typing this on is a 4770 with DDR3-1600. I only run three cores because the fourth is basically useless. :)

[petrw1]

Originally Posted by Prime95

Memory bandwidth bottleneck is back big-time with the Haswell -- especially with standard DDR3-1600.

If it is temp related throttling, then it will happen nearly immediately.

OK....so knowing that ... 2 questions:

1. Without opening the box how can I find out what kinds of RAM there is? I don't see it in the Device Manager.

2. Assuming it is DDR3-1600 is there a better (less RAM intensive) worker setup I can choose? I probably do NOT want to do PM1 or ECM correct? Would running 2 workers (2 pairs of CPUs each help? or be worse?)

My timings are currently way off my Benchmarks (which I realize are near optimal conditions with only 1 worker running at a time).

Benchmarks says 68M LL should be about 20Ms .... with 2 LL/DC workers I was getting 33Ms; with 3 LL/DC workers it went to 48Ms.

Benchmarks says 36M DC should be about 11Ms .... with 2 LL/DC workers I was getting 16Ms; with 3 LL/DC workers it went to 33Ms.

I now have 3 of 4 workers doing LL/DC ... I suspect it could get worse yet in a few days when the 4th starts LL/DC.

Mark may have it right....4 LL/DC workers appears to be too many.