Well, that's disappointing .... R9 7900X3D

[Saracen999]

I've just watched Steve's 7900X3D review at GN and, as I was waiting for this with a degree of intention to jump on it, there's no other way to sum up (well, maybe one way, see note below) other than £disappointing.

I'm certainly no hardware guru but my takeaway, and Seve wasn't exactly subtle, is "give this a miss". There's zero real gain, and some losses, against the 7900-non-X3d in productivity but you pay a premium for the X3D. And the 7900X3D is not exactly a bargain basement option, and if I;m in the market for a $600 chip, then I can certainly push it to a $700 chip and go 7950X3D. If the $600 is pushing it, then I either ought to go 5800X3D (assuming continued availability) for gaming, or 7900-non-X3D for productivity.

Even then, there seems to be some doubt about benefits of the yop tier or two unless also running a very hairy-chested muscle-bound GPU, like 4090. I might fund the higher CPU but don't see myself stumping up for a 4090. In fact, currently, I'm thinking more Team Red GPU than Green, anyway, as ray-tracing isn't a priority but the H.265 encoding could be useful.

So .... if 4090 is out, and my use case is only partly gaming, and at least partly productivity stuff (mainly video), then :-

- top-tier nVidia GPUs are just too expensive for my taste.
- R9 chips so far with X3D aren't giving their best short of top-tier GPUs

I'm kinda thinking, is it worth the pretty big jump in price, in my real-world usage? Probably not.

I am now waiting with anticipation to see how the 7800X3D fares when released, abd hoping that the reason it's later than it's big brothers is because it's close enough to their performance but significantly enough cheaper to risk undermining 7900 and even 7800 in their X3D variants.

If not, I'll probably just drop back to vanilla 7900.

Oh,, and for me, 13700, 13900, etc are non-starters 'cos I'm not willing to go W11 to do it. Not until/unless absolutely forced.

The 7900X3D being a bit pointless has kinda beggar'd up what I thought I'd do. Damn. Glad I waited for testing.





NOTE : My opinion is based on current (i.e. AMD) pricing. My conclusion might well change if this drops a fair bit in actual retail price. Maybe I should say "when" it does.

[ik9000]

ORRRRR I can sell you an i3-540 for lets see, inflation, covid, brexit, cost of living, Tory government, war in East Europe, China hoarding resources, silicon "shortage"

yeah that'll be just £15pm for 24 months. Sounds crazy doesn't it, but...

[ik9000]

Back on track, I was disappointed they didn't do a 5950X3D. I was hoping to upgrade, but now I'll just save to a whole new system at some point. Probably a 7950X3D or its newer variant when I do.

[MrJim]

I'm hoping that at some point the cost of stacked cache will come down, such that it can be put on multiple CCDs without being prohibitively expensive, which would make CPUs like the 7900X3D & 7950X3D a much more desirable proposition. Doubtful for this generation though, I imagine.

[Saracen999]

I'm hoping that at some point the cost of stacked cache will come down, such that it can be put on multiple CCDs without being prohibitively expensive, which would make CPUs like the 7900X3D & 7950X3D a much more desirable proposition. Doubtful for this generation though, I imagine.

Yeah, the current range is a bit 'left hand giveth, right hand taketh away' innit?

Left hand = really fast cache, but
Right hand = slower base clock, plus only half cores cached, other half turned off.

Result = very much depends on the ability of whatever you're running to use whichever feature.

[Percy1983]

I do feel kind of lucky I am 'stuck' with and X570 board and 64GB ram and what was formally a 3700x.

The no 3D versions of the 5900x/5950x in some ways muddied the water but also made the choice easier, as its mostly productivity I went for the 5900x, but also in games it not the difference isn't massive if anything with some games, + neither is going to push my Vega 56 any harder and with current GPU pricing it may be staying a long time.

[Saracen999]

I do feel kind of lucky I am 'stuck' with and X570 board and 64GB ram and what was formally a 3700x.

The no 3D versions of the 5900x/5950x in some ways muddied the water but also made the choice easier, as its mostly productivity I went for the 5900x, but also in games it not the difference isn't massive if anything with some games, + neither is going to push my Vega 56 any harder and with current GPU pricing it may be staying a long time.

Yeah, you are. In all honesty, if I had that spec, I wouldn't be looking at upgrading because yes, it would do. But I'm looking at buying now (well, -ish ) and given the performance differences (at a cost difference admittedly) choosing to go that route now is a different kettle of fish to sticking with it if I had it. The upshot is, in deciding whether to spend £x on the previous gen, or £x+£y on the current gen, do I get enough benefit from it to justify the £y? Given that I'm expecting this machine to last as long as my last desktop build did, it'll probably be the last PC I ever buy. That puts a different focus on it for me than if I thought in 3, 5 or 7 years, I'd be doing it all over again. And that is also why I'm considering a GPU at the level (and these days, prices dammit) that I honestly never thought I would - because hopefully, in a few years once the "new & shiny"-ess of it has long worn off, it'll stay relevant and capable for a bit longer if I go a bit more upmarket with it now.

If I were buying for 3-5 years, I'd probably already have X570 / 5900X, though maybe 'just' 32GB. That is what I intended when I started this 'journey', and t's a pretty strong spec. It's really just my circumstances that has ne even thinking current gen. So yup, you're lucky, not least 'cos getting my brain wrapped round all this is giving me a serious headache.

[[GSV]Trig]

x570, 5800x, 64Gb and a 3080FE will last me a while yet..

I was talking to Zak the other day and I'm hoping the 8xxx series APU's will give us something decent in the iGPU side so I don't need a GPU at all and can just run an APU instead...

[DanceswithUnix]

That was quit interesting viewing.

So it's a game oriented chip, but when running games it turns off half the cores and basically becomes a 7600X3D. For the long haul, 6 cores doesn't seem enough. It looks like the 7800X3D should be able to beat it, so AMD will be down clocking it so that it artificially stays respectfully behind the 7900X3D in the charts.

Having said that, I suspect all of these products will give a superb user experience. The 7900 (non X) machine I built at work very much impressed me, even down to the integrated graphics. So much grunt, and it hardly got warm even with the stock box heatsink. If I didn't already have a 5900X I would be rather tempted.

[MrJim]

Yeah, the current range is a bit 'left hand giveth, right hand taketh away' innit?

Left hand = really fast cache, but
Right hand = slower base clock, plus only half cores cached, other half turned off.

Result = very much depends on the ability of whatever you're running to use whichever feature.

From what I've seen in the reviews, the 7950X3D works very well well when the software stack - bios, chipset drivers, Windows scheduler etc are set up correctly. Even then though, it seems that some games don't correctly use the CCD with the vcache. I'm sure the situation will improve in time, but the beauty of the 7800X3D will be not having to deal with such headaches.

[kompukare]

I'm hoping that at some point the cost of stacked cache will come down, such that it can be put on multiple CCDs without being prohibitively expensive, which would make CPUs like the 7900X3D & 7950X3D a much more desirable proposition. Doubtful for this generation though, I imagine.

Yes, if stacking and tiles really catch (and the end of node progression really means they will) then in the near(ish) future the LEGO-like approach should make all kind of which were previously unviable (but note that Nvidia would never abandon making a halo SKU even if they couldn't sell it elsewhere - unlike Intel or AMD they put a huge amount at being at the top of benchmarks even if only very buy at the top).

All those thing us enthusiast have asked about:

An APU with full cache or even 3D cache?
An APU with a full iGPU chiplet?

And so on. Parts which are very much halo (so for me look at but probably never buy!), and low volume but with building blocks they suddenly become viable.

Of course, chiplets/tiles are not 3D stacking. Rumour is that with Meteor Lake Intel are going to go mobile-first (or mobile-only - but it looks like there will be some desktop chips like with Broadwell that time), so will see how they handle power consumption as the interlinks with chiplets does come with power penalties.

[Saracen999]

That was quit interesting viewing.

So it's a game oriented chip, but when running games it turns off half the cores and basically becomes a 7600X3D. For the long haul, 6 cores doesn't seem enough. It looks like the 7800X3D should be able to beat it, so AMD will be down clocking it so that it artificially stays respectfully behind the 7900X3D in the charts.

...

Except that, presumably, they'll cache one of two core dies and turn off the other, on a 7600X3D too, similarly reducing core count. And that's even assuming they ever make an X3D version of the 7600. I am aware of x£D versions of 7800, 7900 and 7950, but 7600? Not that I've noticed and, of course, the lower down the price scale we go, the less viable the highly expensive cache memory becomes. Is it viable on the 7600, while still keeping the price low enough not to tread on the toes of higher-piced processors? I have some doubts, but hey, my skills in chip design are abut as good as they are in brain surgery or particle physics.

....
Having said that, I suspect all of these products will give a superb user experience. The 7900 (non X) machine I built at work very much impressed me, even down to the integrated graphics. So much grunt, and it hardly got warm even with the stock box heatsink. If I didn't already have a 5900X I would be rather tempted.

Well, yes, quite, on all points.

But none are exactly cheap. And when spending a good chunk of wedge, my preference is certainly to maximise "user experience" for the money. That is where, at least for me, it gets tricky. I mean, as with just about everything else, the product bands are explicity and specifically designed to prod us all into thinking "well that's nice, but for just £x more I can get an ABC instead. And then repeat, until you hit ether top tier or yur absolute maximum budget. And Intel mess it up a bit too (unless you're Win11-averse like me) by offering a completely different principle of operation with chips that are at the very least competitive, if in differents ways, at all the same rough price points. And of course, factor in mobo costs while you're at it, and at least for AMD, RAM too. As I don't have DDR4 (other than in laptop) anyway, the latter doesn't affect me much.

So it's as much or more about getting as good a user experience with this rather than that, at the same or lower price. And, if I just spend an extra £x .... I could go up a level and, at least in theory, get an even better UX.

As a mate of mine from my OcUK days used to say ... "Me 'edd 'urts."

[CAT-THE-FIFTH]

AMD was being cheapskates with this range by only use one chiplet with 3D V-Cache. It wouldn't surprise me if the Ryzen 8000 series end up having dual chiplets with 3D V-Cache. Otherwise you are relying on the Win11 Schedular,or some way of manually assigning games to the proper chiplet. Reviews show the Ryzen 9 7950X has scheduling problems,as a simulated Ryzen 7 7800X3D beats it many times.

The Ryzen 9 7900X3D due to it only having six cores on the 3D V-Cache chiplet,means it is going to be problematic if a game uses 7 to 8 cores.

So IMHO,the only SKUs which make sense with Socket AM5,especially with the ripoff pricing of the motherboards are the Ryzen 7 7700/7700X and Ryzen 7 7800X3D for gaming,and the Ryzen 9 7950X for productivity(because its the best SKU). The Ryzen 7 7900X is actually cheaper per core than a Ryzen 7 7700/7700X so probably is better value for productivity than a Ryzen 7 7700/7700X.

However for gaming,none of the pure six core chiplet SKUs make sense due to the ripoff platform prices,and the fact I am uncertain about the longevity of a 6 core CPUs. The Ryzen 9 7900X will still have the problem,if that any game goes over six cores,there is a latency hit moving to the second chiplet. When you need to spend over £200 just to get PCI-E 5.0,and still close to £200ish to get a reasonable AM5 PCI-E 4.0 motherboard,I see no value preposition in the Ryzen 5 7600/7600X. Even the A620 looks to essentially double prices of the A520 and looks like it will start at well over £100. Basic B650 motherboards with PCI-E 4.0 should be starting at closer to £100,not well over £150 with the last generation connectivity and the fact that Intel can offer PCI-E 5.0 under £200. This is on top of the ripoff mini-ITX motherboard prices on AM5.

[DanceswithUnix]

Except that, presumably, they'll cache one of two core dies and turn off the other, on a 7600X3D too, similarly reducing core count. And that's even assuming they ever make an X3D version of the 7600.

They probably won't actually make a 7600X3D, but basically:
* 8 core and under parts tend to be single ccd (I think there has only been one that wasn't)
* The 5800X3D was single CCD
* The 3D cache extends the L3 cache, which is shared by all cores on the CCD

so if they did make one, I would expect 6 cores all covered by the extra cache. They could only fit half the cache (ISTR there are two cache chiplets involved so they could put a dummy on one side) but that would probably just dilute the 3D branding.

Anyway, my point was that with the 7900X3D for gaming you only get 6 cores, and that doesn't feel like something I would want to drop a lot of money on. Right now there seem to be some games that benefit from the 7950X3D having 8 cores during gaming, and that proportion is only going to get higher over time.

OFC to balance that, those cases that prefer 8 cached cores the 7900X3D still isn't actually slow, but you've paid that premium for speed.

,if that any game goes over six cores,there is a latency hit moving to the second chiplet.

Annoyingly I think that is often due to poor coding. I seem to spend a lot of time explaining cache tiling and cache line eviction to programmers having pointed out bits of their code that could easily go so much faster. If two threads use variables that are too close to each other in memory, then you get expensive cross core traffic for no good reason. That was fine (possibly even beneficial with an overall lower cache working set) in the days of a single core running multiple threads, but I haven't seen a single core machine in how long at this point?

[Saracen999]

They probably won't actually make a 7600X3D, but basically:
* 8 core and under parts tend to be single ccd (I think there has only been one that wasn't)
* The 5800X3D was single CCD
* The 3D cache extends the L3 cache, which is shared by all cores on the CCD

so if they did make one, I would expect 6 cores all covered by the extra cache. They could only fit half the cache (ISTR there are two cache chiplets involved so they could put a dummy on one side) but that would probably just dilute the 3D branding.

Anyway, my point was that with the 7900X3D for gaming you only get 6 cores, and that doesn't feel like something I would want to drop a lot of money on. Right now there seem to be some games that benefit from the 7950X3D having 8 cores during gaming, and that proportion is only going to get higher over time.

OFC to balance that, those cases that prefer 8 cached cores the 7900X3D still isn't actually slow, but you've paid that premium for speed.


...

I did wonder about that when I posted. I mean, if they can cache 8 cores by doing one chiplet on the 16-core part,, presumably they could cache all of the 8 on a single chiplet 8-core part.

But will they?

I struggle to believe they're dumb enough to produce a lower tier card, at a signicantly lower price, that matches performance that closely, at least in gaming, and thereby undermines something further up the product line. Which suggests to me that something will curtail performance of the 7600X3d (assuming there ever is one), and if not by similarly disabling 50% of cores to cache the other half, it'll be something else, like maybe reducing base or boost clock. Whatever. But something that differentiates the layers.

I mean, this kind of product segmentation goes on in just about every industry, and has for decades. I remember covering it in the marketing element of my degree, in the 70s, though it arguably wasn't as revalent then, as now. But look at segmenting of, say, channel 'bundles' on 'cable' TV services, or spec's of mobile phones, or car models (L, DL, GL, GT, GTX, Ghia, whatever). Oh, and camera models, higfi models, and so on. It's a rather tawdry and cynical ploy but, I guess it still works. It does on me. I ended up with a cable package with about 300 channels, and probably 270 (maybe 280) I never watch, but to get the dozen or so I do use, I needed one from this group, a couple from that, and so on.

You can't even uy a box of eggs without braving the product matrix, and not just for size (which is fair enough, I guess).

The end result is I'm not willing to take a punt on a processor choice yet, without seeing benchmarks for the chips were still (and no doubt, it's no accident) waiting for. What doesn't help my choice is that whatever I get is a bit of an indulgence, given that nothing is necessary, and anything is a want, rather than a need. It would be easier if I were a dedicated gamer with no care for productivity, or this was a business buy and I cared about productivity tools that largely benefit from raw grunt that caching, because then, the 79xxX v 79xxX3D (too many x's in there) would be much simpler, but given pretty much a 50/50 spread, and it being need not want, it isn't easy to see the best choice. Common sense tells me to just get a 7900X and a decent GPU and to hell with X3D, but ..... FOMO, y'know.

[DanceswithUnix]

I did wonder about that when I posted. I mean, if they can cache 8 cores by doing one chiplet on the 16-core part,, presumably they could cache all of the 8 on a single chiplet 8-core part.

But will they?

I think they have to have all 8 cores with vcache.

They did on the 5800X3D, so if they don't on the 7800X3D then there will be benchmarks where the older CPU beats the newer one.

That also fits the expected frequencies where the 7800X3D is downclocked, and then presumably, like the 5800X3D, locked so you can't just clock it back up.