Help with a new PC build

[Romeo Delta]

Good day. I need some advice on what to purchase for a new PC build, which will be used for P3D, and other work applications like Excel.

CPU: I've narrowed the CPU down to the 8700k, or 7900x. From my research on this site, it appears P3D is primarily going to benefits most from single core clock speed, which would put the 8700k somewhat ahead of the 7900k. At least in single thread gaming benchmarks, it appears the 8700k is 10% faster, whereas in multicore benchmarks (ie >4) the 7900k leads but this appears to be for mostly business applications. What I like about the 7900k / x299, is the quad channel memory, and larger CPU cache size, but from what I have read the quad channel memory has little to no benefit for games and is meant for video rendering, etc. The biggest question is does P3D take advantage of the additional cores of a 7900x, versus the 6 cores in the 8700k. Can I save $800 buying the 8700k and still get "relatively" the same performance in P3D?

Video: Nvidia 1080 ti (extreme). I am buying two 4k monitors (for work), and would run P3D on a single monitor. Is one 1080ti extreme capable?

Ram: Trident Z 32gb of 16 CL, 3200. Is 32gb sufficient?

SSD: Samsung 960 pro.

If there are any other suggestions, please let me know. I greatly appreciate any feedback as I want to get this right. I typically keep my PC's for 5-8 years.

Again, thank you for any feedback and suggestions!

RD

[StargazerFSE]

Hi RD,

I am building a couple systems very similar to your specs.

I think you're on the right track, from what I've determined from numerous forums and many months of research, P3D v4 performance is highly dependent on single thread CPU performance (clock speed), while cache sizes, hyper-threading, and number of cores will play a role as P3D will use all cores available (on default affinity mask settings). Anything with a BASE clock over 4-4.5ghz should do really well. Boost clocks depending on CPU do not boost all cores, sometimes only 1.

For my builds I will be running the i9-7900X with all cores overclocked to somewhere around 4.5 - 4.8ghz.

If you plan to run a single GPU then most CPUs like the 8700K will have plenty of PCI lanes, however I will be running 2x GTX 1080ti overclocked, so having more then 16 native PCI lanes on the CPU is ideal at least for me, something to keep in mind if you ever want a 2nd GPU.

Another thing to consider is if you plan to run this system as you said 5-8 years or so, is the i7-8700K has a max RAM capacity of 64GB, and most Z370 based motherboards (that I know of), only do 32GB max. So that may be a future bottleneck, at least until if/when they come out with motherboards capable of 64gb.

As for the 1080ti being capable of 4K, I would say absolutely.

Good luck with your build, hope it works out for you.

[Tobago]

I was about to start another thread with a very similar question so I hope you wont mind adding my voice to yours RD.

With the advent of v4, I will now acquire P3D and shall abandon FSX. I will order a new PC very shortly exclusively to run P3D v4.

From the two above posts, I understand that either the new i7 8700K or i9 7900 X will be adequate to run it, however, since I am usually changing my hardware once every six years or so, I'd like to go for the best possible combination available today, so my question is would a i9 7980 XE be better than an i7 8700K, or would the performances be about identical. I must say that I am a bit lost in this maze of single core vs multi core CPU and the price differential - although quite substantial -between the two is not the primary concern to me, I want to be sure I get all the possible performance I can.

The GPU will be a Volta as soon as available next year, and for the time being a EVGA 1070 that I already own.

Thank you for any clarification and help.

[StargazerFSE]

From the two above posts, I understand that either the new i7 8700K or i9 7900 X will be adequate to run it, however, since I am usually changing my hardware once every six years or so, I'd like to go for the best possible combination available today, so my question is would a i9 7980 XE be better than an i7 8700K, or would the performances be about identical. I must say that I am a bit lost in this maze of single core vs multi core CPU and the price differential - although quite substantial -between the two is not the primary concern to me, I want to be sure I get all the possible performance I can.

Hi Tobago,

While I think the 8700K is a great CPU and very affordable, personally I would have to lean toward the 7900X in terms of performance. If you compare the number of cores alone you get you'll see the 7900X's 20 cores wins out over the 8700K's 6, while it has a faster core speed, it's down on cores. For a crude comparison you can imagine cores as 1" garden hoses spraying water at lets say 30 psi, would 6 at a slightly higher pressure fill a swimming pool faster then 20 at a slightly lower pressure?

Another consideration for future proofing is the 8700K's max of 64GB RAM, and only 2 memory channels, while that's more then enough now it may not be in the future, and the 7900X has plenty of room with 4 channels (quad channel) and 128GB max.

You also have to consider how CPUs and threads get scheduled on Windows, and how hyper-threading and single-core performance play into this. Prepar3d v4 at the moment does really well with most CPUs over the 3.5 ghz area or faster, and while having a CPU with lower number of cores (maybe even an i3-8100) and speed over 3.5 or 4 ghz would be a good setup for any video card, a cpu with similar speeds and lots of cores would be much better to divide the load better, and for future scaling.

Also the 7900X is by default under the 3.5 ghz mark for base clock speed, which is something to consider if you don't want to venture into the world of overclocking, you would probably want to bump the base clock above 3.5 and probably ideally into 4 ghz territory, keeping in mind that the "turbo" clock speeds don't boost all cores on Intel CPUs, only 1 or 2 usually.

For price to performance, I would probably avoid the 7980XE and it's nearly $2,000 price tag, while it would perform great if you look at it from a cost perspective you wouldn't gain much ground over a 7900X or even an 8700K for that matter.

I hope that helps explain things for you, and also the GTX 1070 is plenty of GPU just about any CPU.

[Tobago]

Many thanks Matt, your reply is very detailed, easy to comprehend for a non specialist like me and indeed informative.

I now understand the real benefit of i9 vs i7. So I will narrow down my choice between the i9 7900X you suggested and perhaps a i9 7940X, the difference between the two is really in the number of cores 10/20 vs 14/28 and the cache sizes L2 10/14 (L3 is not known on the documentation I read). I wonder which one P3D would work better with since the base clock is 3.3/3.1 and max boosted to 4.5/4.4 (in this case 7900X looks marginally better but has more cores to offer)?

If I believe what I read on several sites, an OC close to or equivalent to 5.0 GHz on both should be possible although the wattage consumption will sizably increase hence a good cooling with a Noctua NH-D15 and several additional fans to extract the heat from the box would be needed...

Is my analysis correct? Again many thanks for your kind help.

[StargazerFSE]

Many thanks Matt, your reply is very detailed, easy to comprehend for a non specialist like me and indeed informative.

I now understand the real benefit of i9 vs i7. So I will narrow down my choice between the i9 7900X you suggested and perhaps a i9 7940X, the difference between the two is really in the number of cores 10/20 vs 14/28 and the cache sizes L2 10/14 (L3 is not known on the documentation I read). I wonder which one P3D would work better with since the base clock is 3.3/3.1 and max boosted to 4.5/4.4 (in this case 7900X looks marginally better but has more cores to offer)?

If I believe what I read on several sites, an OC close to or equivalent to 5.0 GHz on both should be possible although the wattage consumption will sizably increase hence a good cooling with a Noctua NH-D15 and several additional fans to extract the heat from the box would be needed...

Is my analysis correct? Again many thanks for your kind help.

Hi Tobago,

I would say you're on the right track, and it really comes down to how many years you want to get out of the PC. While the i7-8xxx series has less cores, less cache, and less pci lanes then the i9-7xxx series, the i7 is quite a bit cheaper and is still a very capable CPU, keeping in mind where the limitations are.

Me personally I chose the i9 mainly because of PCI lanes and cores, since I'll be running dual Asus GTX 1080 ti OC 11gb cards. It beats out some of the older i7 chips in a few areas like more cache and number of cores. There are some older for example i7-69xx stuff that also has enough PCI lanes, however when compared to the i9 in terms of number of cores and cache size the i9 has the older stuff beat (obviously).

So even if you did go with the i7-8xxx series I think it would still run v4 great along with your 1070, but you'll be limited to 32gb of ram, and less cores, etc.

Now in terms of overclocking the i9, while it can reach 5ghz, actually getting it there would require a "good" CPU, due to variations in production of the CPU dies, some chips can be more or less capable in terms of how far you can push them. And with a conventional heatsink and fan type of cooling setup like the Noctua (which is really good) I can tell you right now, you will not be able to overclock much past probably 4ghz at the most, maybe less. The i9 can create massive amounts of heat and I have seen various reviews and posts relating to this where the power draw can be very high (over 600 watts).

To give you an idea of what I'm planning to run for cooling on the 2 systems I'm building for a Prepar3d v4 project right now, I'm running the i9-7900X, 32GB of DDR4-3200, dual 1080s like I mentioned, M.2 512GB SSD, and plan to overclock to at least 4.5 - 4.8 ghz. The cooling setup is a hard line single pump/loop, dual 560mm (4x140mm) radiator custom design with forced air A/C being pushed into the bottom of the case from the raised flooring system. Each radiator can dissipate around 1000 watts of heat given the right conditions (room temp/humidity/etc).

To answer your question about what Prepar3d v4 would do best with 3.3 or 4.5, with default settings (no affinity mask), as far as I am aware Prepar3d will use logical core #0 for it's rendering tasks and will pretty much max out that first core and be limited by the clock speed in how fast it can render. Now there are settings you can tweak to modify this and spread the load out over the cores in different ways, but that's a separate and somewhat advanced topic. You want the highest possible clock speed for at least the first CPU core (over 3.5 ghz).

Respectfully,

[Tobago]

Thank you again Matt, I really appreciate your guidance and detailed explanations, they are helpful. And now the hard part starts, quite a number of days of work before the first P3D take-off !
Happy landings!