CPU upgrade.. go for Cores or L3 cache?

[Schmafuzius]

Hello,

I am thinking for a long time now to update my rig since its not really a new one anymore... Still not too bad and I can run DCS but when I see some of the Screenshots in here I want more and some stutters are starting to really annoy me..

Anyway..

Currently I am running a 1600x and my Mainboard would be able to run a 5800X3D or a 5900X

Price is pretty the same at the moment (the 59000X is slightly cheaper) but the big question is now on the impact of multithreading ...

The 5800X3D is still THE CPU to go for gaming with the huge L3 cache but the 5900X has more cores and I wonder if DCS would benefit from the additional cores more than from the higher L3 cache..

Had anyone the opportunity to compare these two, because I really dont know what to go for...

 

Next question will be GPU then... 

[some1]

5800X3D. 

DCS won't benefit from the extra cores on 5900

[Rudel_chw]

29 minutes ago, Schmafuzius said:

Had anyone the opportunity to compare these two, because I really dont know what to go for...

 

I haven't, but according to tests the 5800X3D seems a bit better performer:

 

 

[Schmafuzius]

thanks for your answers...

I saw that video with the comparison between the two CPUs but on the other hand I wondered if these games really use multithreading since it is not that common in games (yet)..

That is where I thought if DCS counts as game or as a multi-core application in this scenario... 

[Hiob]

I had both tested back to back in my system. The X3D performs about 20% better than the 5900X. Currently it has more than enough cores also. DCS using/needing more than eight cores is far far future at best.

Edit: Full disclosure. I still kept the 5900X, because most of the time I'm GPU limited anyway - and outside of gaming, I thought the 5900X is a better choice for me. Only considering gaming, the 5800X3D would be a no-brainer for me.

Edited November 22, 2023 by Hiob

[Hiob]

52 minutes ago, Schmafuzius said:

The 5800X3D is still THE CPU to go for gaming with the huge L3 cache but the 5900X has more cores and I wonder if DCS would benefit from the additional cores more than from the higher L3 cache..

To answer this specific question. I think the MT DCS is currently using 4 Threads at a time max. Try to find the newsletter where they introduced MT. IIRC @BIGNEWY stated precisely how many cores are used and what for specificly. 

I limit my CPU to six cores (one ccd) currently, because it seems to help with the current stutter issue. But apart from that, there is no impact on performance whatsoever.

Even outside of DCS, in really modern games like Cyberpunk or something, there is no real gain in additional cores past six to eight as far as I'm aware of.

Edited November 22, 2023 by Hiob

[BitMaster]

With the Radeon 580 you won't see any difference between them as you will be GPU limited.

I like my 5900X but the 5800X3D might be the better choice if you look at your VRM. Depending on how robust your VRM you can support more Cores and more ampere.

I just flew a test round with the new patch, my CPU is constantly between 85-100w when flying DCS. It's not overclocked, rather the opposite, it's undervolted.

The 5800X3D will not pull that much. I just built a 7800X3D with a 7800X and that drew less watts than mine in most games I tested. The more cores you have the higher the idle and overall

power draw, keep that in mind. My CPU idles with 40-60watt up&down. That a waste just because of 12 cores idling along. The X3D counterparts stay much more in a sane limit while

the still deliver the punch in DCS and most other games too. I'd take the X3D if you don't heavily multithread otherwise and can make use of the cores.

Edited November 22, 2023 by BitMaster

[SkateZilla]

5800X3D or 5700X3D,

5600X3D was a microcenter exclusive, but in reviews was already bottlenecking due to less cores and lower TDP.

the 7K Series, don't go higher than the 7800X3D, because then you'll have two CCD's one w/ VCACHE, one without, and you;ll have to disable the 2nd CCX to keep the Vchache cores from dumping work to the other CCX.

 

Edited November 25, 2023 by SkateZilla

[Mr_sukebe]

X3D.

The AMD “all our cores are full cores” is both true and misleading at the same time.

Yes, the cores are the same.  However, AMD only put 8 cores on each CCD, meaning that their current 16 core CPUs have their “full cores” spread over two CCDs, which are on a single CPU socket.

Unfortunately, whilst they’re good cores, it seems that the CCDs don’t talk that well to each other, meaning that for gaming, only one CCD can be effectively addressed, ie 8 of the cores.  The other 8 can happily go off and run background activities, but not the game. So right now, neither Intel or AMD sell what is “gaming” CPU that can genuinely run more than 8 full cores.  The roadmap from AMD suggests that the next version (2024) won’t give us a solution.

It’s just a bit pap that you have to dig around to find this stuff out.

So back to your question, for DCS, the X3D version

[Schmafuzius]

thanks for all your help..

After looking into the upgrade thing a bit deeper I might change plans...

With the CPU and the GPU upgrade I would end up in changing my PSU aswell where I reach the point of overthinking the whole upgrade idea...

Black Friday did not have the discounts I was hoping for and my current system is still running as it is...

I guess after christmas I will start a completely new rig, possibly running a 7800x3d... 

[SkateZilla]

21 hours ago, Mr_sukebe said:

X3D.

The AMD “all our cores are full cores” is both true and misleading at the same time.

Yes, the cores are the same.  However, AMD only put 8 cores on each CCD, meaning that their current 16 core CPUs have their “full cores” spread over two CCDs, which are on a single CPU socket.

Unfortunately, whilst they’re good cores, it seems that the CCDs don’t talk that well to each other, meaning that for gaming, only one CCD can be effectively addressed, ie 8 of the cores.  The other 8 can happily go off and run background activities, but not the game. So right now, neither Intel or AMD sell what is “gaming” CPU that can genuinely run more than 8 full cores.  The roadmap from AMD suggests that the next version (2024) won’t give us a solution.

It’s just a bit pap that you have to dig around to find this stuff out.

So back to your question, for DCS, the X3D version

Intel has their Cores in Unified groups as well, it's not a CCX issue.

AMD's issue is X3D Cache is only on one CCX, so when a program is moved to the other CCX, performance suffers.
Non V-Cache CPUs the performance is the same regardless of the CCX the thread is placed on.
It's Multiple CCXs and MCDs on an Infinity Fabric on a single substrate package.

CCX's will not get larger than 8 cores anytime soon due to optimal yield size being 8 cores, as all 8 Cores can architecturally be linked in processing, moving to more cores in the CCX will drastically increase the size of the CCX.

Windows 11 is supposed to recognize the processor and limit gaming to a single CCX to decrease latency and cache jumping.

[Mr_sukebe]

1 hour ago, SkateZilla said:

...CCX's will not get larger than 8 cores anytime soon due to optimal yield size being 8 cores, as all 8 Cores can architecturally be linked in processing, moving to more cores in the CCX will drastically increase the size of the CCX...

 

Agreed, though I'm still hoping that the ever decreasing size of the lithographic techniques will eventually allow more than 8 cores, though being fair, maybe we'll all be running ARM by then.

I just feel a bit miffed that the current improvements are mainly in IPC, as we've already reached the current effective limit of cores.

 

[SkateZilla]

1 hour ago, Mr_sukebe said:

 

Agreed, though I'm still hoping that the ever decreasing size of the lithographic techniques will eventually allow more than 8 cores, though being fair, maybe we'll all be running ARM by then.

I just feel a bit miffed that the current improvements are mainly in IPC, as we've already reached the current effective limit of cores.

 

If they fix the VCache heat and cost issue, they'll likely just start building them with vcache dies inbetween the 2 CCX's allowing both CCX's access to the entire pool of L3.

The new threadripper is 64c/128t at 350w TDP (uses about 600w overclocked w/ PBO)

Cores isn't the problem, heat dissipation is, the smaller everything gets, the less interface material there is to move the heat off of the CPU.

ie, the ThreadRipper 64c Chip, is huge, and the heatspreader is around 4x the size of the 7900 series CPUs, 
The thing hits 5 GHz on 64 Cores while remaining under 70°C.

Edited November 26, 2023 by SkateZilla

[Mr_sukebe]

So, imagine that we had a 32 core threadripper (I seem to remember DCS-MT being limited to that), and water cooling using a fishtank next to the PC (bearing in mind some of the cockpits out there, I could picture someone doing that), do you think that we could run more than 8 cores effectively?

My current understanding is that the 4 CCDs would struggle to coordinate.

Thoughts?  Has ED tested DCS-MT with a threadripper?

[Schmafuzius]

1 hour ago, Mr_sukebe said:

So, imagine that we had a 32 core threadripper (I seem to remember DCS-MT being limited to that), and water cooling using a fishtank next to the PC (bearing in mind some of the cockpits out there, I could picture someone doing that), do you think that we could run more than 8 cores effectively?

My current understanding is that the 4 CCDs would struggle to coordinate.

Thoughts?  Has ED tested DCS-MT with a threadripper?

I did not find the post from ED but I think to recall that DCS MT is limited to 8 threads (or cores?) at the moment anyway...

[Hiob]

This is what I had in mind:

Doesn‘t sound like eight threads to me, and I certainly never seen it use eight.

 

[SkateZilla]

More threads isn't always better.

[Hiob]

8 minutes ago, SkateZilla said:

More threads isn't always better.

Agreed. Depends on the task(s) at hand.