7800x3d or 7950x3d

[roland6885]

Hi all, planning a new pc build and cannot decide between a 7800x3d or 7950x3d. I heard because of the way the 7950x3d has to shut down half its compute cores for gaming it may not be better than the 7800x3d , despite its l3 cache advantage. Anyone know which cpu would be better to play x3 and x4 with? I’m currently maxed out on graphics with a 4090 so that isnt my concern atm

[CBJ]

Moved to the off-topic forum, where hardware recommendations belong.

[BigBANGtheory]

7800x3d if your primary workload is gaming
7950x3d if you game and use demanding productivity apps regularly

I use a 7800X3D with a 4090 myself, I don't think X4 will use the additional cores of the 7950 in any meaningful way tbh X3 certainly won't

[af_2017]

Ryzen 9 7950X3D has 5.7GHz boost clock speed against 5GHz on 7800x3d.
So specifically for this single core game you will be able to handle slightly more turrets on your stations with the same fps.

[CBJ]

So specifically for this single core game you will be able to handle slightly more turrets on your stations with the same fps.

I'd just like to point out that this statement isn't entirely accurate. It's true that X4 often benefits more from higher clock speeds than from more cores, because the clock speed of the core running certain parts of the main simulation will often be the limiting factor, but it's certainly not a "single core game". It will make good use of many cores for lots of other tasks.

[af_2017]

I'd just like to point out that this statement isn't entirely accurate.

I agree, it's a matter of wording.
X4 is not able to utilize all 8/16/32 cores.
While this is true more horse power of a single core is better for the game for higher performance.

[jlehtone]

Ryzen 9 7950X3D has 5.7GHz boost clock speed against 5GHz on 7800x3d.

AFAIK:
* The 7800x3d does have one 8-core CCD and the 3D cache on top of it.
* The 7950x3d does have one 8-core CCD and the 3D cache on top of it and other 8-core CCD without cache on top.
The cache on top limits the boost clock. Hence you can boost to 5.7 GHz on a core that has no fast access to extra cache,
or you can run on core that has more cache but won't boost as high (but still a bit higher than 7800x3d).

Whether CPU/OS/you can distribute the threads of X4 to "appropriate" cores on 7950x3d is ... not known (to me).

[roland6885]

So a 7950x3d would be better for x3 and x4? i didn't realize there were 2x the cores in a 7950x3d than a 7800x3d. so regardless of the application, the 7950x3d should *theoretically* outperform but for whatever reason, the vids on youtube comparing fps of the same game on the same gpu shows the 7800x3d beating out the 7950x3d in almost all games.

[af_2017]

but for whatever reason, the vids on youtube comparing fps of the same game on the same gpu shows the 7800x3d beating out the 7950x3d in almost all games.

Just to check this statement I picked random video: https://youtu.be/KaFysypIs0k
7800x3d is better only in two games of 10 tested games; interesting that both games are ported from playstation;
and event so I would not call that fps difference "beating out".

[matthewfarmery]

So a 7950x3d would be better for x3 and x4? i didn't realize there were 2x the cores in a 7950x3d than a 7800x3d. so regardless of the application, the 7950x3d should *theoretically* outperform but for whatever reason, the vids on youtube comparing fps of the same game on the same gpu shows the 7800x3d beating out the 7950x3d in almost all games.

I saw this video

https://www.youtube.com/watch?v=wf9ww8XE3Xk

While the 7950x3d does have more cores, it seems from that above video, enabling those cores and getting them to work can be fiddly. While if you go for a 7800x3d, its way simpler. So more cores isn't actually a good thing, unless the game is programmed to use those extra cores.

So really, the 7800x3d is probably the better choice.

[af_2017]

AFAIK:
* The 7800x3d does have one 8-core CCD and the 3D cache on top of it.
* The 7950x3d does have one 8-core CCD and the 3D cache on top of it and other 8-core CCD without cache on top.
The cache on top limits the boost clock. Hence you can boost to 5.7 GHz on a core that has no fast access to extra cache,
or you can run on core that has more cache but won't boost as high (but still a bit higher than 7800x3d).

Whether CPU/OS/you can distribute the threads of X4 to "appropriate" cores on 7950x3d is ... not known (to me).

That's a good point, thanks!
It's good to know that 7950x3d is actually 7950x1.5d because of the fact.
How things being managed by OS is explained here: https://youtu.be/qq13-xxAVDE

[felter]

It all depends on just what you are going to use the computer for if it's just or mainly games then get the 7800, if you are mainly using it for 3d rendering, video editing or the likes with the occasional gaming session then you should get the 7950. When it comes to gaming, there is little to no difference between them when there is a difference, the frame rates are so high the difference doesn't matter. The 7800 uses less power so costs less to use and because it uses less power it creates less heat meaning less cooling and a potentially longer life span, and with less cooling comes the lower noise as the cooling fans are not being used as much. But as I said it all comes down to what you are going to use it for, or of course you could go for the 7950 just so you can go I have a 7950 in my system, if you’re so inclined.

[Panos]

I'd just like to point out that this statement isn't entirely accurate.

I agree, it's a matter of wording.
X4 is not able to utilize all 8/16/32 cores.
While this is true more horse power of a single core is better for the game for higher performance.

On Linux X4 uses all 16 cores of my 5950X as did with the 12 cores of the 3900X (SMT off) and can see the extra performance compared to Windows even if I am GPU bound.
Give it a try, you will be surprised when you see X4 sprawling across the CPU and is not the first game that does so these days.

[linolafett]

I would go for the 7800x.
I got the7950x as i do 3D works with this machine, but almost everything runs now on GPU anyways and things which are on CPU are often not time consuming enough to warrant the few more cores.

[Imperial Good]

For gaming you almost always want the 7800X3D. Currently most games do not scale past 8 cores well, and the additional cache is such as a performance boost that the high frequency cores on the 7950X3D often end up dragging down performance due to being slower if the game accidently ends up using them. Situations where the high frequency cores can out perform the cache cores are quite rare, and often limited to productivity applications which either do not benefit much from cache, or that the smaller cache is already large enough. When using the 7950X3D and the scheduler is working correctly, you might find that as good as all the time is using the 8 high cache cores, with the 8 high frequency cores rarely seeing much use despite you having paid for them.

There is likely one exception to this that I know of. City Skylines 2 will likely benefit from the 8 additional cores on the 7950X3D over the 7800X3D, allowing a significantly bigger city before running into performance limits. Then again this is also the only game I know that seems to benefit significantly from running on a high end HEDT system over a high end consumer CPU system.

As far as X4 goes the 7800X3D will likely offer the optimum performance. X4 does not benefit well from high core frequency since it is prone to becoming cache miss bottlenecked. Although the physics should scale with core count, the chance that the critical path task might end up scheduled to the slower, high frequency, cores rather than the faster, high cache, cores might undo any potential performance benefits of the 7950X3D. If the 7950X3D is faster, the difference is unlikely to justify the higher cost over the 7800X3D.

[EGO_Aut]

Its not on the topic, but whats with the 7900 x3d?
Some weeks ago, i did read about a software update or something, to profit from the higher frequency and make it in games faster than 7800 x3d?

[Arsaneus]

Its not on the topic, but whats with the 7900 x3d?
Some weeks ago, i did read about a software update or something, to profit from the higher frequency and make it in games faster than 7800 x3d?

I use the 7900X3D and I am very happy with it. Though I would agree with the others to get the 7800X3D if gaming is the focus as it is fast enough for other every-day workloads. Core parking works fine if set up correctly but the only reason to get the 7900X3D is if you also have some heavy workload other than gaming (virtualization, rendering, etc.) Maybe also for streamers (not something I'd know well). Then it also depends how much the price gap is in you are as the 7950x3d would simply be better for heavy workloads (or future-proofing).

[Imperial Good]

Its not on the topic, but whats with the 7900 x3d?

That CPU has 6 high cache cores and 6 high frequency cores. For games that use 6 or less threads then it might perform better, like the 7950X3D, if the high cache cores can reach a higher frequency. As soon as a game uses 7 or more threads it will likely perform worse as it would have to use the slower, high frequency, cores that are also on another CCD.

It is not that the 7900X3D and 7950X3D are bad CPUs, just their use case is rather niche. Most applications and even operating system schedulers do not know how to handle high cache cores vs high frequency cores in a sensible way, resulting in the stupid situation where in order to get the full performance of the high cache CPUs it turns off the high frequency CPUs. This kind of defeats the purpose of having paid the extra money for a CPU with them, when using them is actually detrimental to a lot of applications. On the other extreme, if you want a lot of cores for your productivity workloads, but do not want to go all in on HEDT/server, then Intel's high end desktop is very competitive as it offers more cores and has a significantly lower cache miss penalty across them all.

Hopefully AMD moves more towards an Intel style layout, where it offers the high performance, high cache, cores as "performance" cores, and then uses AMD's space/energy efficient, Zen 4c style, cores for the additional chiplet as "efficiency" cores. For people who need the extra cores this would double the additional cores available to them (8 high cache, 16 general purpose), and from a software perspective it is easy to manage with some core prioritisation (active process on high cache, background and overflow on general purpose). Unlike Intel's E cores, these are architecturally the same as the high cache cores as well.

[Youngman]

Hi Everybody

I would go for the 7800x.
I got the7950x as i do 3D works with this machine, but almost everything runs now on GPU anyways and things which are on CPU are often not time consuming enough to warrant the few more cores.

That's good to know!
I've just (last week) managed to collect the last items of a new computer build, based around an AMD Asus Rog Strix B650E-F Motherboard (DDR 5 ATX), and with the Ryzen 7 7800x3D CPU.
Also some Corsair DDR5 Ram (32GB), a new PSU (Seasonic 1000W ATX3.0), also a new 'mid'? range AMD Radeon GPU. (MSI AMD Radeon RX 6750 XT Gaming X Trio)...well it was sorta mid range just a few months before last Christmas!
Oh!. forgot to mention, a new monitor as well, a Gigabyte G24F2 'gaming monitor'.

Anyway, The comp. case I already have, and some SSD drives from the old computer. (A 1TB + 500gb) plus a W. Digital 3.5" x 1Tb Sata 3 drive I can use that for storage etc.). An M2 drive would have been better as the main C drive obviously, but at the moment they will have to do. I haven't started on the new build yet due to other RL commitments, but I should be making a start on it in the next month or so.
Wish me luck!

Oldman

[linolafett]

[...], but I should be making a start on it in the next month or so.
Wish me luck!

Oldman

Good luck!

PS: If you still want to recover access to your old account, pm me!