7800X3D, 7900X3D, 7950X3D..

[Gman109]

Thanks for the posts - 7800X3D it looks like then.  Just went on sale here in Canada too at my shop.  

[Joao Fonseca]

Hello all,

I'd like to kindly ask for your advice here on my PC build if you don't mind.
I already have ordered all the parts except the CPU. I went to an AM5 setup with a 32GB DDR5 6000MHz CL30.

I'll use the PC mainly for DCS and X-Plane 12 and some productivity software. My doubt is what CPU I should look for? 
7800X3D seems a good candidate but for $100 more I can get the 7900X3D which has a higher clock speed and more cores. I can also consider getting the 7900x or 7950x.
7950X3D is very expensive for me.
My current GPU is a NVIDIA 3080. Probably will update the GPU in about 1 year.
No VR, 1 monitor only.

Any advice would be much appreciated!

[kksnowbear]

54 minutes ago, Joao Fonseca said:

Hello all,

I'd like to kindly ask for your advice here on my PC build if you don't mind.
I already have ordered all the parts except the CPU. I went to an AM5 setup with a 32GB DDR5 6000MHz CL30.

I'll use the PC mainly for DCS and X-Plane 12 and some productivity software. My doubt is what CPU I should look for? 
7800X3D seems a good candidate but for $100 more I can get the 7900X3D which has a higher clock speed and more cores. I can also consider getting the 7900x or 7950x.
7950X3D is very expensive for me.
My current GPU is a NVIDIA 3080. Probably will update the GPU in about 1 year.
No VR, 1 monitor only.

Any advice would be much appreciated!

It was discussed just a little above your query:

On 10/17/2023 at 6:35 PM, Biggus said:

I suspect this is because of the configuration of the 7900X3D and 7950X3D.  They are dual CCD, with the stacked cache only on one of the CCDs.  The 7800X3D is a single CCD.  For DCS, the 7800X3D should be the pick of the bunch because of this.

On 10/17/2023 at 6:53 PM, kksnowbear said:

Beat me to it But yes, this is pretty much the way it is.  It's the cache that gives these X3D chips their advantage, and only half of the 'cores' in a 7950/50X3D have access to the cache.

And for whatever it's worth, although the MT patch has helped, DCS is still a long way from what I'd call "good" core utilization...so having a lot of extra cores doesn't really make a lot of difference.  The majority of a CPU's ability is sitting there bored, based on what I've seen first hand.

For the price, (IMO of course) the 7800X3D is still the way to go.

[Joao Fonseca]

35 minutes ago, kksnowbear said:

It was discussed just a little above your query:

For the price, (IMO of course) the 7800X3D is still the way to go.

Thanks, much appreciated!

[hannibal]

2 hours ago, Joao Fonseca said:

Thanks, much appreciated!

i just bought 7800x3d eariler this week. system passed memtestx86

i picked this becasue 

"A Ryzen 7900X3D has two six-core chiplets, but only one has 3D V-cache. Only one chiplet can game at a time, meaning it's really only a six-core CPU when gaming.

The 7800X3D has one eight-core chiplet with 3D V-cache."

[Joao Fonseca]

43 minutes ago, hannibal said:

i just bought 7800x3d eariler this week. system passed memtestx86

i picked this becasue 

"A Ryzen 7900X3D has two six-core chiplets, but only one has 3D V-cache. Only one chiplet can game at a time, meaning it's really only a six-core CPU when gaming.

The 7800X3D has one eight-core chiplet with 3D V-cache."

Thanks for the info, nice to know!

So seems that for those who have the money the choice will be 7950X3D because it has 16cores with two CCD chiplets with a significative higher clock speed (5.7GHz vs 5.0GHz of the 7800X3D)

[Mr_sukebe]

40 minutes ago, Joao Fonseca said:

Thanks for the info, nice to know!

So seems that for those who have the money the choice will be 7950X3D because it has 16cores with two CCD chiplets with a significative higher clock speed (5.7GHz vs 5.0GHz of the 7800X3D)

 

Be careful with where you're going on that thought.

Yes, the 7950 does have x2 CCDs, each with 8 cores.  However, I get the impression that the two CCDs don't have infinite bandwidth and ability to communicate between each other, meaning that in practical terms, it's more like the Intel style of 8 performance and 8 additional cores, those those additional cores do run quickly.

[Biggus]

8 hours ago, Joao Fonseca said:

Thanks for the info, nice to know!

So seems that for those who have the money the choice will be 7950X3D because it has 16cores with two CCD chiplets with a significative higher clock speed (5.7GHz vs 5.0GHz of the 7800X3D)

It depends on what you're wanting to do.  If you're doing productivity stuff and simming isn't your main focus of your build, yes, a 7950X3D is probably the better choice.  But if you're building for flight sims, no, the 7800X3D is the better choice.  The higher clocks don't necessarily mean better performance.

[Hoirtel]

10 hours ago, Joao Fonseca said:

Thanks for the info, nice to know!

So seems that for those who have the money the choice will be 7950X3D because it has 16cores with two CCD chiplets with a significative higher clock speed (5.7GHz vs 5.0GHz of the 7800X3D)

Also higher clocks only on non-cache cores, vcache cores clock the same as the 7800. So the 7950x3d is a bit like a 7800x3d and a 7700x in one chip, i.e jack of two trades. Any all core workloads will use all 16cores but half will be 5ghz. Games are supposed to use the vcache side and there is some software (windows game mode) to encourage this. 

As already mentioned there is possible issues with the translation between two ccds. Also as mentioned it depends on your requirements if best gaming is you thing then 7800, it will do other things, just not quite as fast as a higher clocking chip

[Joao Fonseca]

Many thanks for all your feedback, really appreciated!

Indeed I'll be using the PC most of the time for gaming. Also there is a substantial cost increase of buying locally the 7950X3D vs 7800X3D so it had to justify the extra money which seems not to be the case at least for my purpose.

Edited October 27, 2023 by Joao Fonseca