Core i9 7900x vs 7920x vs 7940x - which one to buy

J

JargonGR

Limp Gawd
Joined
Dec 16, 2006
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503
Well I am torn between the three chips for my upcoming build so any input from people using them would be appreciated.

So here is the scoop;

Let's assume that price is not a factor between the three which one would you choose based on the following:

Motherboard will be: Asus Rampage VI Extreme
RAM: 64GB 3600 or 3800 either G.Skil Trident Z RGB or Corsair Dominator Platinum.


1) Overclocking. I might not overclock straight away but I want to have this option in the future and I am also willing to delid but not initially. I am upgrading from a Q9550 @ 3.4Ghz at the moment so performance increase will be big anyway.


2) Heat & Overclocked heat in the future. The system will be watercooled with a fully custom loop using an EK monoblock and a huge MO-RA3 9 X 140mm Radiator. Can add more in the future if needed.


I have not found much information on the 7920x & 7940x overclocking results but the few instances I have found look good. It seems that the whole line-up overclocks easily to at least 4.6Ghz and you can still overclock only certain good cores only if you want.

Now I want to have some faster cores for certain applications where Ghz matters.

Finally, I have read some views stating that the larger dies of the 7920x & 7940x might be easier to cool because of the larger surface area but don't know what to think of that.


What would you buy?
 
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7940x for sure - if you can find one. I have not even seen a review yet.

They seem like the best chip since tdp is higher and you get the best combo of cores and clocks.
 
Well I am in Europe and I can see it in stock here and there plus I am buying as company so I am not being charged VAT so the price is a bit smoother to swallow.

As you might have noticed I am upgrading from an ancient Q9550 so performance difference will be great anyway and I plan to keep this chip for at least 3-4 years. With that said, it's good to have headroom.

This PC is also making me money and will be using it for content creation, running a localhost web servers for testing and also will play around with 3Ds Max and Adobe After Effects. My workflow also demands that I have many things open at the same time (Photoshop, Illustrator, 2-3 Browsers with LOTs of Tabs and developer tools open, Outlook, Adobe Bridge for library asset management, Font Managers and more). Add 1-2 VMs for testing as well and I can see utilizing those cores pretty nice.

I have not played a game for the last 7-8 years but I would like to play again from time to time (limited time) since I completely stopped watching TV during the last years (only read news from the net) so I saved my self some time there. I am getting a 1080Ti in this build and a new 4K monitor sometime next year so it would be fun.
 
You WILL have to delid period.

I run a 7820x because it has faster IPC and clock potential for gaming and still has a decent core count for multithreaded material. As far as the 14 core you will not have the same single core performance because you wont be able to run the chip as fast unless you do some weird per core OC setup.

Also keep in mind that many games will actually choke if they see more than 20 threads available. I had this issue on my 1950x and had to use affinity to get the games to load. GTA V comes to mind as one of them.

And a 9x 140mm radiator? You are purely wasting your money. It is not going to make the chip run at room temperature no matter how much water you throw at it. It will just be a big ugly mess of a giant un needed radiator.

You do not need 2kw worth of cooling potential. A single EK 3x120mm is keeping my dual 1080ti's @ 2012mhz and 7820x at 4.8ghz all core cool with no effort at all.

However since you made no mention of gaming and just mentioned doing work to make money and you also made mention that you have money with no issues spending it, I would just urge you to get the 7980extreme. It is absolutely going to be a monster at work threads. Or a Threadripper 1950x for pure work.

Hope that helps in your planning.
 
hey tangoseal thanks for the input,

I know I will delid in the future but reports from many users ( I am watching several other forums) show that for mild overcloks it might not be absolutely necessary depending on the chip that you get (e.g. a 7920X @ 4.8Ghz without delid exists). It seems that the latest batches of HCC SKUs have better TIM application. Nevertheless, will get one and will take it from there. I will also get a Rockit 99 delid tool but won't take the risk immediately although it seems really easy from all the vids I've seen. It is only warranty that holds me back and until I have a second CPU I might not touch it.

Regarding the RAD, yes it is big but will be placed & decorated properly while I have plans on moving it to another room. This is for fun too but I really don't want ANY restriction as far as cooling capacity goes and want to try this rad with the fans at low RPM (hell even with less fans) or even connect a second system to it. It won't be ugly - this can be sorted out easily through the proper mods.

Processor wise, I mentioned that price is not a factor between the three. I can't justify a 7980X right now no matter how awesome it is so I am settling on the 7940X since I also need a lot of other components (4K monitor, WACOM tablet, Pro A3 printer, Calibration tools, etc, etc.). Yet, since I am planning to build 2 more systems I can always grab one in the future when I won't have all this pressure with other gear.


Finally - games! It's been a long time since I gamed but my son is now 10 years old and I don't want him playing stupid tablet games so I am getting into some light PC gaming again. However, yes gaming is not something I really care when it comes to configuring this system. I know it will be able to play 1 game or 2 per year if I decide to do it.
 
I mean it's really up to you on what you get. You mention that you will be making money with it. Do the programs that you use take advantage of many cores? Is it worth it to you to spend ~$500 on 4 extra cores? I know you said money doesn't matter but $500 is a good chunk of change. If you're really going that overboard with your cooling system then temps shouldn't weigh in on your purchase. Gaming will be great on any of them so no help there either. Really it comes down to if you think your applications and actual usage will take advantage of the additional cores.
 
It would be helpful if there was some overclocked bencmarks for the 7920x and 7940x.

The 7960x performs very close to the 7980xe when both are overclocked. If the 7940x does as well, it would be worth the money.
 
Lol, I am scouting all the overclock.* forums I can find for info but it seems that there are not many 7940x out there in the hands of overclockers. Nevertheless, from the tons of reading I have done till now there is nothing worrying me regarding the ability of the 7940x to reach a 4.6Ghz speed without much effort. Plus there is the option to fine tune further going with per core overclock.

custom90gt said:
I mean it's really up to you on what you get. You mention that you will be making money with it. Do the programs that you use take advantage of many cores? Is it worth it to you to spend ~$500 on 4 extra cores? I know you said money doesn't matter but $500 is a good chunk of change. If you're really going that overboard with your cooling system then temps shouldn't weigh in on your purchase. Gaming will be great on any of them so no help there either. Really it comes down to if you think your applications and actual usage will take advantage of the additional cores.
Click to expand...

Well yes, this machine will be used daily for content creation that is indeed a good source of income for me (and rising). Regarding multicore usage, I am planning on doing some 3D rendering and video processing while running 2 VMs at least and a localhost webserver for testing. In any case I want to have cores to spare or to lend to certain tasks between my team if needed.

Anyway I have placed the i7940x on my shopping basket for now and even though its more expensive I am sure I won't regret it and will be put to good use and will last me a long time.
 
Well I will order everything but the RAM / GPU to gain some time since I will only be able to devote time to setting up this new PC after the 5th -10th of January.
I hope that RAM prices come down a bit after Christmas but what I read points to other conclusions. I know they will come down eventually but it might take more months.
And it really is important to get a QUAD kit to be sure that all modules will work together nicely and this has been the recommendation of both Asus and G.skill. Otherwise, I would get let's sya 16GB and add more a bit later.
 
I think you should go with at least 32GB if you're really going to have VM machines and the like. 64GB is probably better...
 
custom90gt

I am indeed going with 64GB not only for VM machines but for many more reasons:

A) Photoshop with 1GB Files open + Illustrator, Bridge, Office (3 apps), Acrobat DC + Browsers with many tabs + VM + Autocad on request

B) Adobe After Effects (gobbles up RAM like there is no tomorrow)

I am also using Windows 10 desktops and it is not rare to have 2-3 desktops with a project open on each and all the software associated with my workflow.

If prices were better I would go for 128GB but as it is now I am not doing it. Maybe in 1-2 years I can dump the 64GB Quad kit to another machine (or two) and get a 128GB kit at probably much lower price than now.
 
Well I ended up with an i7940X but unfortunately I won't be able to test until I have all the parts for my new system.

Right now I have the MB - Asus Rampage VI Extreme, RAM - 64GB Trident Z RGB DDR4 3600, GPU - Asus Strix 180Ti OC, CPU - i9-7940x, SSD - Samsung 960 Pro, CASE - Cooler Master Cosmos 2 (had that new in its boxe - never used before) -will order a side window for it soon.

And......... I don't have : the PSU (Corsair AX1500i - paid and on order since the 30th of November) and all the watercooling gear that will place on order in January.

I am staring at those cool toys and can't use anything - DAMN! Only a new Logitech MX Master 2S that I got in order to use for 2 PCs at the same time. It's cool but I want to play with the other toys......
 
Looks like you will to have one of the best syestems on here, and the only 7940x afaik. I think you just made alot of people [H]ard.
 
It's been a long time since I needed an upgrade though - I am working on a Q9550 with 8GB RAM and GTX780 + Samsung 840 Pro. I can't wait to feel the speed difference + new possibilities on content creation tasks (3Ds Max + Adobe After Effects).

Once I am up and running (whenever that is) I will start a thread for the 7940x if none has started one till then. I wonder what it can do.
 
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