AMD Ryzen 7000X3D CPUs Launched: Ryzen 9 7950X3D Offers Big Gains and Efficiency

MojoKid writes: At CES 2023, AMD unveiled an array of Ryzen 7000 series Zen 4 processors, including new gaming-targeted X3D models that featured integrated 3D V-Cache, similar to the Ryzen 7 5800X3D. The processors go on sale tomorrow, but review embargos for AMD's latest socket AM5 flagship, the Ryzen 9 7950X3D, lifted today. As its name implies, the new Ryzen 9 7950X3D has a similar core configuration to the existing Ryzen 9 7950X (16-cores/32-threads), but this specialized CPU also packs an additional 64MB of 3D V-Cache, fused to one of its 8-core compute core dies (CCD). The CCD without 3D V-Cache operates like a standard AMD Ryzen 9 7950X, while the 3D V-Cache enabled CCD will have a more conservative voltage and frequency curve. Gaming performance received a massive boost with this new CPU, while multi-threaded content creation tests are roughly in-line with the standard 7950X. Power efficiency also shows a large, measurable improvement due to the chip relying less often on system memory.

Caveats

[Chas]

You're going to need to be on the latest available BIOS and you'll need software (essentially the XBox bar) to get the most out of it.
Mainly because what it does is shuts off half the cores, as the amount of memory per chiplet isn't symmetrical.

This kinda argues against the 7950 X3D from a pure value standpoint.
Especially since the core frequency is lower than the standard X chip.

Now the 7900 may be a better value, as you deal with fewer cores that aren't impaired by this behavior.

But the 7800 will likely see negatives as it's supposed to be down-clocked from the X variant.

Hopefully the next-gen version of the X3D will function more like E--core/P-Core architecture. So that the OS just KNOWS which cores see the extra cache and can select them based on gaming/productivity parameters.

Still, when the extra memory means something, it REALLY means something.

Re:Caveats

[Guspaz]

> But the 7800 will likely see negatives as it's supposed to be down-clocked from the X variant.

On the contrary, the 7800X3D avoids all these scheduling problems requiring special software support and game bar and such because it doesn't have heterogeneous chiplets like the 7900X3D and 7950X3D. Both of which advertise their boost clocks based on their non-X3D chiplet. I'm not sure what the real X3D boost clocks of the 7900X3D or 7950X3D are, but the 7800X3D and 7950X3D have the same base clock, so their X3D boost clock is probably not too different.

Re:Caveats

[UnknownSoldier]

> the 7800X3D avoids all these scheduling problems requiring special software support and game bar and such because it doesn't have heterogeneous chiplets like the 7900X3D and 7950X3D

Exactly. HUB (Hardware Unboxed) benchmarked a simulated 7800X3D [youtu.be] by disabling the second CCD on the 7950X3D in BIOS calling it a "7800X3D simulated". With Factorio results were:

* 5800X3D = 352 FPS
* 7950X3D = 249 FPS
* 7800X3D simulated = 433 FPS

> I'm not sure what the real X3D boost clocks of the 7900X3D or 7950X3D are,

AMD states [amd.com] a boost up to 5.7 GHz. Under workload with both CCDs the 7950X3D clocks around 4800 MHz on CCD1 and 4900 MHz on CCD2 with Cinebench R23. [youtu.be] Disabling the second CCD is probably why the simulated 7800X3D showed a whopping +73% faster uplift in Factorio because it could hit the boost clock.

Re:

[Chas]

I'm always reticent to put any store in "simulated" benchmarks.
We'll see when the part actually makes it to market.

Re:

[UnknownSoldier]

It goes without saying that one should ALWAYS wait for benchmarks before buying.

Once the 7800X3D ships / embargo lifts and the reviews are live then we can see the actual performance difference between the real 7800X3D and the "simulated" 7800X3D which should be negligible.

Re:

[chefren]

I heard that AMD is working with Microsoft to actually get the OS to know which cores have the extra cache. In the one reviews I have seen, they showed that some applications (mostly games) benefited a lot (up to 30%), others not so much and there are even some use cases where the net result of extra cache and lower clock speeds ends up being negative. The review concluded that the not yet released 7800X3D might be a better choice for gamers and advised to wait until April when its launched and make the c

Re:

[aRTeeNLCH]

Regarding the BIOS caveat, one really neat thing is the AM5 socket standard to be able to flash the BIOS without a CPU or memory installed. On my AM4 board, my 2400G didn't post, the board had an older BIOS (6 months), the 3 months old update was the first one suited for my CPU. I actually had to go out and buy another CPU to flash the BIOS. Luckily I could return that one with mild penalty...

good cpu, but very niche

[jarkus4]

Seems like a nice CPU, but also extremely niche: in most productivity workloads regular 7950x is faster, while in games you have to disable half of the cores (those without extra cache) to get benefits. To make it worth using in practice you need a workload that can make use of both this extra cache of some cores and raw power of a full core count.

I expect that 7950X (productivity) and future 7800X3D (gaming) will relegate this CPU to mere curiosity for most potential buyers.

Re:

[AmiMoJo]

I can see it being popular with gamers whose workloads are 90% games, or where they only play 10% games but really care about that performance and can live with other tasks being a little bit slower.

I'm waiting for the laptop versions and hoping that this generation finally makes me want to upgrade.

Re:

[bill_mcgonigle]

This one feels more like a technology demonstrator than an endpoint product.

We'll probably look back in two more generations and point to this one as where certain technology got started.

At some point you just have to build the damn thing to find out if it actually works. Then iterate.

Thank goodness AMD is actually keeping CPU innovation alive. Probably time for Intel to sue them again.

Re: good cpu, but very niche

[Type44Q]

We'll probably look back in two more generations and point to this one as where certain technology got started.

Let me know when low-latency DDR5-8000 is a thing; until then it's a moot point - except for those wanting to drive 480hz displays.

Not impressed

[Sqreater]

They have to add a couple more zs and xs and many more numbers and perhaps a cubed root or two before I'm impressed.