OMG Batman!!!!!

[Psi*]

The new build, Asus P6X58D + I7920 + Corsair Dominator RAM + Win 7 + uber WC, up & running tho not completed. It is OC-ed to al-l-lmost 4 GHz. Much to be done there ...

Speedfan reports the max temp for a core of the upper 40s degree C. It is very noisy since the per core load varies so much. The average CPU temp is around 33 deg C.

BUT, this is more than 10X faster than the dual Opteron 290s I have. For everyone's reference, that machine is 4 years old & has 16 GB RAM & cost >$6K. This new box cost under $2K.

Someone said on some forum (pretty sure it was *not* here anywhere) that Windows 7 optimized the load of multi-threaded apps more evenly across the processor cores. In a word, NO! I don't know why or how it should or could.

I am running a number cruncher (CST TD) that took a week to run on the Opteron box ... I will have to look back at the absolute numbers, but this machine that is only using half the available CPU (4 threads) looks like it will finish that same problem in 8 to 10 hours. My license is currently limited to 4 threads. The next version due in a couple of weeks will be limited to 16.

I have a nother number cruncher (Microstripes) that always uses all available cores. I will fire it up later. The problem I will throw into it took 4 days on the Opterons. This program also gets 100% CPU utilization so SpeedFan numbers ought to be equally as interesting.

wPrime 64 bit was about 6.7 secs. Sorry for not putting up more digits, as if another hundredth or thousandth makes a difference, but I just thought that I would throw this out.

KUDOS to Rob. You the man!! You suggested I go for the I7 920 and save $800 over the I7 975 as well as getting this m/b. Can you imagine what the hexa-cores will do?! I am back to interactive design again!

 

[Doomsday]

hey good going man! Congrats!

now, to The Topic!

wheres Batman?!?
lol!

 

[Kougar]

Glad to see you're enjoying your new system! It never gets old hearing how some people are amazed at the performance jump...

Someone said on some forum (pretty sure it was *not* here anywhere) that Windows 7 optimized the load of multi-threaded apps more evenly across the processor cores. In a word, NO! I don't know why or how it should or could.

It doesn't distribute the load itself evenly, that would hurt performance. What Windows 7 does is avoid shuffling active threads onto sleeping cores when it can place them elsewhere. It is hyperthreading aware, so if given a choice between a logical or a physical CPU with zero load, it will always choose to place the load on a physical CPU for best performance.

 

[Psi*]

So Kougar, w/o quoting everything that you just said ... I was watching one of my number crunchers start up late last night. This program runs in 3 parts; pre-processing, solver, & post processing.

The solver is the exciting part (at least for those days when I don't get out often) in that it is multi-threaded & it is pretty neat seeing all 8 CPU histories in Task Manager fill up. And just to get it out of the way, post processing is always quick single threaded stuff for looking at the results of the solver.

The pre-processing can take many minutes if not an hour or 2 and is single threaded. What I was watching last night was on the longer side. I was actually watching Task Manager & the 8 CPU usage histories. In TM only the even (& all of the even) numbered CPUs were active for a total of 11% or 12% ... 1 thread's worth of crunch in other words. The odd numbered CPUs stayed at zero. No surprise given that this part is just plain old sequential code.

So since the odd numbered CPUs are not real as they exist in hyper-space I guess ... I'll call it, this still suggests to me that Win 7 does not let sleeping cores lie.

On the other hand, I am an OC-er & in looking for every possible CPU cycle, I have disabled in bios anything that would shut cores down, aka put them to sleep. So perhaps this is the difference in your assertion & my assumption?

 

[Psi*]

4.2 GHz

I had a moment to play & just bumped the I7's clock to 4.2 GHz. SpeedFan shows the highest temp of any core using "toast" is 53 deg C; lowest is 45 deg C, "CPU" is 39. ... haven't touched any voltages. I'm diggin' it

 

[Kougar]

If the core isn't powered down, then yeah that might have something to do with it... Windows would see a fully powered, waiting, idle core and dump work onto it. I'm not going to say Windows 7's multithreading capability is perfect, I've seen it bounce a single thread across four active cores before. What I did say is that it should not bounce it across a parked core or a logical HT core unless it needs to.

 

[Psi*]

K!

I guess I had disassociated multi-threading with the OS. I started to get innto multi-threaded coding when it was becoming available to the "pedestrian" ... moi. But there are only so many hours in the day & I stayed with hardware to become only an appliance operator of the codes I wanted to write.