7700K, 8700K, 7740X?!... That is the question.

[betelgeuse 41]

I am planning a new build to run P3D4 and possibly X-Plane 11.

Regarding CPUs I am confused about 'cores' and their importance in P3D4. 

I am also confused about 'delidding' as applied especially to Coffee Lake CPUs.

Could someone enlighten me please, as non-technical as possible.

John

 

[Noel 4,496]

On 10/26/2017 at 4:30 AM, betelgeuse said:

I am planning a new build to run P3D4 and possibly X-Plane 11.

Regarding CPUs I am confused about 'cores' and their importance in P3D4. 

I am also confused about 'delidding' as applied especially to Coffee Lake CPUs.

Could someone enlighten me please, as non-technical as possible.

John

Sure, I'll try ;o)

Both P3DV and XP can use more cores than the typical 4-core CPU found in common gaming rigs of the recent past.   They don't use each core the same way:   most of the processing work needed to make the sim run, sometimes called 'the main thread' is done on only one of a multi-core CPU.  This means that what is referred to as 'single-core performance' of a given CPU arguably has the biggest impact on what role any CPU can play in either flight sim..   A CPUs single-core performance is generally based on two things: it's 'IPC', or Instructions Per Cycle as a part of it's logic architecture, and it's 'clock speed', expressed in Gigahertz.   Over the past 6 years or so IPC has improved substantially, and clock speed relatively slightly by comparison.  To put it where the goats can get it, my Sandy Bridge E processor, now over 5y/o, runs with all of its 6 cores at 4.42hz on relative low extra voltage, and the latest processors from Intel can run up near or above 5.0Ghz, w/ better IPC.  How big of an impact can we get comparing old SB-E CPU and today's top end processors?  I'm guessing around a 25-35% improvement if the top end processor runs at typical overclocked speeds possible today.  That is significant, while hardly overwhelmingly so.

Beyond the main thread done on one core, other cores are used by both P3D primarily for loading terrain textures.   I think this is true to XP 11 as well, and I think I read that other aircraft traffic in XP is handled in other available cores as well.

If I were shopping now for a CPU I wouldn't buy one with less than 6 cores which is what my SB-E has.   I've seen all 6 of my cores being utilized in P3D and since increases in single-core performance improvements are relatively meager one hopes at some point flight sim software develops to use those extra cores even more than currently is the case.  So while a 4-core CPU may get you slightly more single-core performance since it doesn't have be able to manage the heat demands of larger multi-core processors, the difference between the best 4 core and the best 6+ core CPU in terms of single-core performance isn't that large.  Therefore, I lean towards at least 6 cores, maybe 8 cores, for either flight simulator going forward.

Intel CPUs since Ivy Bridge 4-cores have been manufactured w/o soldering the Integrated Heat Spreader (IHS), otherwise known as it's 'lid', to the CPU's heat producing 'die' where all of the work is done.  They use a Thermal Interface Material (TIM) between die and IHS instead of solder and it is considerably less efficient in transferring heat to the IHS compared to solder.   My SB-E chip is soldered, and runs in the 50-57C temp range w/ all 6 cores running at 4.42Ghz on a Noctua air cooler.  It has become common to see temps in the 70-80+ with processors like the 8700K and that is with water or good air cooling.   By 'de-lidding', removing the IHS and reattaching with a more heat-conductive TIM, not solder, one can get temps lowered by 10-20C.  In general, with overclocking, the higher the clockspeed, the higher the voltage required, and the higher the temperature goes, so de-lidding can help the overclock go as high as it can.   When a CPU gets too hot it is automatically 'throttled back', i.e., it's clockspeed is reduced to help it stay w/in it temperature limits, and no one wants that to happen while flying ;o)

As a side point it's always a good idea if you can afford it to build with the best GPU you can afford along w/ the best CPU.   You've heard by now 'P3D/FSX is 'CPU-limited', meaning as you are flying thru complex scenery the demands of the sim's main thread exceeds what your CPU can do despite its overclocked state.   As well, the same can happen to your GPU since some of the sliders in the sim affect mostly the GPU, whereas others mostly the CPU.   

[betelgeuse 41]

This is just what I was hoping for, Noel. Thanks for taking time to explain these mysteries so clearly.  For the first time I understand why a Kaby Lake i7 at 3.8 GHz  runs faster than an Ivybridge i7 at 3.8 GHz.

The same goes for de-lidding. Just why a manufacturer would create a CPU capable of being overclocked without the necessary built-in heat protection disturbs me. In effect, Intel charges extra for a CPU that can be overclocked, but avoids warranty claims because of the need to de-lid it. A variant of Catch-22. Nice one, Intel!  

In the event, I bought a 8700K-based system with a 8GB GTX 1070 Ti, 16GB DDR5 etc. I usually build PCs myself but this time I'm buying a custom system from Scan PC (UK). This will be for P3D4 and possibly X-P11. I guess I will notice a difference from the Ivybridge set up I've been running for the past 6 or 7 years! 

Thanks again,

John

[warning23 1]

On ‎27‎/‎10‎/‎2017 at 5:25 PM, Noel said:

Sure, I'll try ;o)

Both P3DV and XP can use more cores than the typical 4-core CPU found in common gaming rigs of the recent past.   They don't use each core the same way:   most of the processing work needed to make the sim run, sometimes called 'the main thread' is done on only one of a multi-core CPU.  This means that what is referred to as 'single-core performance' of a given CPU arguably has the biggest impact on what role any CPU can play in either flight sim..   A CPUs single-core performance is generally based on two things: it's 'IPC', or Instructions Per Cycle as a part of it's logic architecture, and it's 'clock speed', expressed in Gigahertz.   Over the past 6 years or so IPC has improved substantially, and clock speed relatively slightly by comparison.  To put it where the goats can get it, my Sandy Bridge E processor, now over 5y/o, runs with all of its 6 cores at 4.42hz on relative low extra voltage, and the latest processors from Intel can run up near or above 5.0Ghz, w/ better IPC.  How big of an impact can we get comparing old SB-E CPU and today's top end processors?  I'm guessing around a 25-35% improvement if the top end processor runs at typical overclocked speeds possible today.  That is significant, while hardly overwhelmingly so.

Beyond the main thread done on one core, other cores are used by both P3D primarily for loading terrain textures.   I think this is true to XP 11 as well, and I think I read that other aircraft traffic in XP is handled in other available cores as well.

If I were shopping now for a CPU I wouldn't buy one with less than 6 cores which is what my SB-E has.   I've seen all 6 of my cores being utilized in P3D and since increases in single-core performance improvements are relatively meager one hopes at some point flight sim software develops to use those extra cores even more than currently is the case.  So while a 4-core CPU may get you slightly more single-core performance since it doesn't have be able to manage the heat demands of larger multi-core processors, the difference between the best 4 core and the best 6+ core CPU in terms of single-core performance isn't that large.  Therefore, I lean towards at least 6 cores, maybe 8 cores, for either flight simulator going forward.

Intel CPUs since Ivy Bridge 4-cores have been manufactured w/o soldering the Integrated Heat Spreader (IHS), otherwise known as it's 'lid', to the CPU's heat producing 'die' where all of the work is done.  They use a Thermal Interface Material (TIM) between die and IHS instead of solder and it is considerably less efficient in transferring heat to the IHS compared to solder.   My SB-E chip is soldered, and runs in the 50-57C temp range w/ all 6 cores running at 4.42Ghz on a Noctua air cooler.  It has become common to see temps in the 70-80+ with processors like the 8700K and that is with water or good air cooling.   By 'de-lidding', removing the IHS and reattaching with a more heat-conductive TIM, not solder, one can get temps lowered by 10-20C.  In general, with overclocking, the higher the clockspeed, the higher the voltage required, and the higher the temperature goes, so de-lidding can help the overclock go as high as it can.   When a CPU gets too hot it is automatically 'throttled back', i.e., it's clockspeed is reduced to help it stay w/in it temperature limits, and no one wants that to happen while flying ;o)

As a side point it's always a good idea if you can afford it to build with the best GPU you can afford along w/ the best CPU.   You've heard by now 'P3D/FSX is 'CPU-limited', meaning as you are flying thru complex scenery the demands of the sim's main thread exceeds what your CPU can do despite its overclocked state.   As well, the same can happen to your GPU since some of the sliders in the sim affect mostly the GPU, whereas others mostly the CPU.   

THANK YOU!!

 

At last someone says it as it is.

The industry ( and the world in many regards ) has gone backwards and processors should be now in the 8 GHz mark, wether you agree or not with multicore perf.

 

 

[Luke 782]

14 minutes ago, warning23 said:

The industry ( and the world in many regards ) has gone backwards and processors should be now in the 8 GHz mark, whether you agree or not with multicore perf.

And planes should be flying at Mach 8, except that they don't and for good reason. There's also a reason why clock speeds aren't much above 4Ghz - it's called the laws of physics. The heat and current leakage as you get above a certain speed gets prohibitive.

AMD and Intel are giving the market what the market wants - the market wants lower power and more cores. Most software has adapted. It says more about us that the simulators have not.

Cheers!

 

[Ted Striker 338]

On 10/28/2017 at 1:55 AM, betelgeuse said:

I guess I will notice a difference from the Ivybridge set up I've been running for the past 6 or 7 years! 

Looking forward to hearing a report on the performance increase as I am still on an Ivy Bridge myself.

Ted

[larshall 4]

9 hours ago, Ted Striker said:

Looking forward to hearing a report on the performance increase as I am still on an Ivy Bridge myself.

Ted

+ 1

[betelgeuse 41]

17 hours ago, Ted Striker said:

Looking forward to hearing a report on the performance increase as I am still on an Ivy Bridge myself.

Ted

I will post again in a new thread. The machine will arrive this week I hope, but it will take me a couple of weeks to get things installed assuming there are no major hitches.

It cannot be a direct comparison as I won't be comparing like with like. My FSX Ivybridge rig has to cope with a vast number of addons and non FS programs which will not be installed on the new machine.

The new PC will have P3D4 and X-P 11 only.

John

 

[z06z33 763]

On 10/21/2017 at 1:21 PM, jmig said:

You can buy 16Gb in 8Gb sticks and then add two more later, if needed.

The issue is those are a mismatched set and my not run at the rated speed together stabily.

[warning23 1]

Quote

And planes should be flying at Mach 8, except that they don't and for good reason. There's also a reason why clock speeds aren't much above 4Ghz - it's called the laws of physics. The heat and current leakage as you get above a certain speed gets prohibitive.

It doesnt if you increase the size, and your comparison with a plane is ludicruous, ( and also wrong since there are planes reaching almost Mach 7 ) because you cant make a plane with engines that use more power due to size, you can though make a pc fast enough with the appropiate size and electric consumption. ( that is of course if you really want to , which is not the case with INTEL )

Quote

AMD and Intel are giving the market what the market wants - the market wants lower power and more cores. Most software has adapted. It says more about us that the simulators have not.

 

AAaaaaah, so now its not the laws of physics but the market. That is actually more correct on your part.

Nevertheless that is not what the market wants. That is what Intel wants because they dont want to spend the money in investigation and better fabrication.

[ahsmatt7 1,199]

I went from a 2700k to an 8700k and saw double the performance gains.

Both these processors were tied with a 1080 ti running at 4k.

Food for thought....

[Noel 4,496]

1 hour ago, ahsmatt7 said:

I went from a 2700k to an 8700k and saw double the performance gains...Food for thought....

So you're saying, w/ your 1080Ti NOT at full utilization, in for example a scenario of extreme processing demand where frame rate was maxed at 24fps w/ your 2700K you now see 48fps w/ the 8700K?  That flies in the face of every other testimony I've seen, and for single-core perf  is way over what other benchmarks of single core performance on those two processors demonstrate.  What exactly are you talking about when you say 'double the performance'?

[Dirk98 354]

I've finally ordered i9-7900X delidded and binned @4.7GHz from Silicon Lottery. With Collaboratory Pro between DIE/IHS/H115i (280mm) and ample 10 Cores (no HT) I hope to achieve working 5.00GHz without much trouble. One of the reasons I got this CPU was it's larger Cache, more CPU lanes  than 8700K, and the fact that it still supports Win7 x64 ( in one of my multi-boots I plan to have some older great games like BoB2, YAP etc. on Win7 x64 O/S).

 

 

Edited November 15, 2017 by Dirk98

[Noel 4,496]

2 hours ago, Dirk98 said:

I've finally ordered i9-7900X delidded and binned @4.7GHz from Silicon Lottery. With Collaboratory Pro between DIE/IHS/H115i (280mm) and ample 10 Cores (no HT) I hope to achieve working 5.00GHz without much trouble. One of the reasons I got this CPU was it's larger Cache, more CPU lanes  than 8700K, and the fact that it still supports Win7 x64 ( in one of my multi-boots I plan to have some older great games like BoB2, YAP etc. on Win7 x64 O/S).

 

 

Awesome Dirk, does Win 7 not support 8700K?

[Dirk98 354]

12 hours ago, Noel said:

Awesome Dirk, does Win 7 not support 8700K?

No, unfortunately not.

Thanks.