Hyperthreading

[Admetos]

I program a neural networks application, the program is multi-threaded so it uses all virtual cores. I actually had the same program running over 3 separate computers simultaneity (multi-threaded and distributed).

To cut to the chase, basically from a coding perspective I treat a hyper-threaded machine as having double physical cores. All the threads were timed and hyper-threading made a massive difference to overall throughput. This was code running on Ivybridge and Haswell i7's compiled on Visual Studio 2013. From my own experience I think hyper-threading is worth it.

 

[easyrider]

I still turn it off

I have now turned it back on!!

Lol

 

[AllBodies]

It definitely does not increase IPC.

I suppose technically I should have said PPC (performance per clock), people tend to say IPC to mean that.

It does not increase the amount of cores the processor physically has, nor increases the clockspeed. So it does increase performance per clock of the CPU.

 

[joeyjojo]

To cut to the chase, basically from a coding perspective I treat a hyper-threaded machine as having double physical cores. All the threads were timed and hyper-threading made a massive difference to overall throughput. This was code running on Ivybridge and Haswell i7's compiled on Visual Studio 2013. From my own experience I think hyper-threading is worth it.

Interesting, how massive is massive? How did you parellelise it (openmp, etc.)?

Not relevant to the OP which is about gaming but I'm curious.

 

[IvanDobskey]

I considered swapping my 2500k out for a 3770k but the cost of doing so isn't worth it in my opinion. The 3770k seems to fetch £150 or more second hand.

I'll stick with the 2500k for another couple of years before doing a full rebuild.

 

[shahpor]

Well, I was bored so I did a little test with Witcher 3.

Here is a rough approximation of the result:

As you can see, the CPU is working very hard. It peaked at 96%.

Although I think it was my 780Ti's that really struggled. Both hit 100% usage at some points. The GPU memory usage seemed ok with 2.7GB's used, although I am not sure if that is just a cap of the total 3GB total? If so, then that is maxed too.

I am beginning to think that more than just a CPU upgrade is going to be needed.

 

[Rroff]

Interesting, how massive is massive? How did you parellelise it (openmp, etc.)?

Not relevant to the OP which is about gaming but I'm curious.

Something like neural networks are potentially a best case (depending on the exact implementation) for hyper threading mind. Someone's AI routines for a game I was working on saw a 70% performance gain from HT enabled versus disabled on a 4 core Intel. Mind you the overall performance difference for the whole game was like 15%.

 

[Admetos]

Interesting, how massive is massive? How did you parellelise it (openmp, etc.)?

Not relevant to the OP which is about gaming but I'm curious.

I had a custom thread scheduler (written in c#) that was firing threads, each computer was set to maintain a pool of 8 threads.

From my experience the performance boost was very almost double. First thread would show 12-13 CPU usage, second 25-26%, four 50-52%, six 75%, all the way to 8 threads showing 100% usage.

The threads were executing as jobs and the results stored in XML, the XML showed all the execution times also.

Remember also I had a modern compiler that was aware of the instruction set on Ivybridge/Haswell CPU's.

 

[Panos]

Well, I was bored so I did a little test with Witcher 3.

Here is a rough approximation of the result:

As you can see, the CPU is working very hard. It peaked at 96%.

Although I think it was my 780Ti's that really struggled. Both hit 100% usage at some points. The GPU memory usage seemed ok with 2.7GB's used, although I am not sure if that is just a cap of the total 3GB total? If so, then that is maxed too.

I am beginning to think that more than just a CPU upgrade is going to be needed.

Extend it to show all cores/thread. (the MSI overlay)

My CPU says in many games that run at 70% and basically two cores runs at 80%-90 the rest 10 (6 core/12 thread CPU) are snoring.

Now regarding your upgrade, 2500/2600K and 3770K not huge perf jump, ain't worth
Start looking for 4770K. That one indeed will provide you with the boost needed

 

[shahpor]

Thanks for the suggestion.

Here is what all my cores are doing:

That is just hanging around the city. As you can see, it is all the cores that are being used heavily.

I did consider the 4770k, but the primary reason for not doing it is the cost. No doubt the 4770k would be a nice boost, but apart from the cost of the cpu, I would be looking at a new motherboard as well. This would push the price up considerably against just getting a 3770k.

So my hope was that, specifically for the games I am currently playing, having the extra cores the i7's provide would prove useful.

Now, based on what was said on this thread, for the cost of the 3770k - minus what I can get for my 2500k - it would make a cheap and reasonably effective upgrade.

 

[Panos]

You need stronger IPC true but 3770K to 2500K difference is not that big.

have a look here, and lets not forget we talk about 4 1/2 years old tech

http://www.bit-tech.net/hardware/cpus/2012/05/01/intel-core-i5-3570k-cpu-review/6

So best solution push the 2500K to 5Ghz, until the next circle of used i5/i7s will hit the MM when Kaby Lake is out. (3-4 months)
You will find a lot of Haswell, Devil Canyon and Skylake for sale.

 

[Disco_P]

Thanks for the suggestion.

Here is what all my cores are doing:

That is just hanging around the city. As you can see, it is all the cores that are being used heavily.

I did consider the 4770k, but the primary reason for not doing it is the cost. No doubt the 4770k would be a nice boost, but apart from the cost of the cpu, I would be looking at a new motherboard as well. This would push the price up considerably against just getting a 3770k.

So my hope was that, specifically for the games I am currently playing, having the extra cores the i7's provide would prove useful.

Now, based on what was said on this thread, for the cost of the 3770k - minus what I can get for my 2500k - it would make a cheap and reasonably effective upgrade.

I have similar issues with Novigrad on my 3570K. 100% usage at 4.8ghz with both an old school titan and a 1080 at 1440p. GPU usage would drop to about 70%. I am fortunate that I didn't get any stutter but know others did. I now have a 2600K to see if hyperthreading helps ready to test but won't have access to my computer for another week.

Upgrading to haswell or devils canyon is a bit pointless as the improvements are <10% which isn't worth the investment into a new motherboard.

 

[shahpor]

Thanks chaps.

I wouldn't upgrade to Haswell or Devils Canyon for the reasons stated. Like I said in the OP, I am looking at a cheap upgrade.

The idea is to use the machine until perhaps Skylake-E or Cannonlake assuming they offer a reasonable performance boost.

Disco, obviously I am interested in your tests with the 2600k, so please let me know how it goes.

I do get a bit of stutter, but then my graphics cards are pretty much maxed as well.

Anyway, the point is, since my cpu is working so hard, I was wondering if the extra cores the hyperthreading allows would make running Witcher easier.

 

[RichardH754]

Seems the same, no difference with it on or off!

 

[shahpor]

Chaps, I picked up a 3770k in the end, but something odd is happening. When I run Prime95, I see this:

You guys have any idea what is going on?

Thanks.

 

[Emlyn_Dewar]

Are you running latest BIOS?

Would be interesting to see a CPU get up to 233 degrees C!

 

[shahpor]

I think so.

I am running 3603, which seems to be the latest one available for my Asus P8Z68-V Pro.

Yeah, I can't imagine it running long at that temp