AM4 > AM5 CPU Question

[Zarginnia]

So atm i have 5800x and wondering wich CPU would be "a smart move" to get.

7800x3D is cheaper
BUT
9800x3D is better but more expensive.
BUT
9900x3D is new and better than both but too expensive.

Im looking at 9800x3D since its better than 7800x3D.
This is my understanding of these CPUs.

[Mabi]

nice to have money to spend, bad not to have many excuses to use so much stuff. better the ryzen 9000 to avoid heat problems. even better to wait for am6 and ddr6.

or better spend more and accept less and less optimization...

[Illusion of Progress]

The 9900X3D is not better than the 9800X3D. Even at the same price, I'd always choose the x800X3D over an x900X3D in the same generation.

The x900X3D in particular should generally be avoided. You need to understand AMD's lineup to understand why. This pertains to desktop CPUs (laptop CPUs are different as they often use monolithic CPUs that don't follow this).

AMD currently makes CPUs out of eight core chiplets (CCDs). This means anything with above 8 cores needs multiple CCDs. That should be easy enough to follow.

Their desktop lineup currently has 4 SKUs; those are a 6 core (Ryzen 5), an 8 core (Ryzen 7), a 12 core (Ryzen 9 x900), and a 16 core (Ryzen 9 x950).

So the Ryzen 7 is a single 8 core CCD and the Ryzen 9 x950 is a pair of 8 core CCDs.

The Ryzen 5 and the Ryzen 9 x900 use 6 core CCDs that had two of the cores disabled (often because they weren't fully functional).

If you ever need to communicate between multiple CCDs, latency penalties are incurred. This shows up as lower performance in "real-time" applications... which games are. For multi-threaded productivity work that isn't real time, the penalty isn't notable (hence the idea that the Ryzen 9s are good choices for highly-threaded work, but less so for purely games).

On top of this, the Ryzen 9 X3Ds don't have the extra v-cache on both CCDs; only on one. Despite the complaints about this, there's a pretty legitimate reason for this (basically, the added performance would be near nil most of the time but costs would go way up, making them even worse of values than they currently are), but it's important to know for the x900X3D SKU in particular since it has less cores per CCD.

TL;DR:

Ryzen 9 x900X3D is 6 cores with v-cache + 6 cores without. Less cores with v-cache plus cross CCD latency penalties.

Ryzen 7 x800X3D is 8 cores with v-cache. More cores with v-cache plus no cross CCD latency penalties to worry about since... it only has a single CCD.

The latter is better performance and cheaper, so for gaming it's a win-win.

[Zarginnia]

ok, thanks!

[matt]

TechPowerUp benchmarked several high end CPUs with a 5090 at 1280x720, which is crazy CPU bound. The 9800X3D still won most of the tests. link[www.techpowerup.com]

But what about the lows? According to TechPowerUp, the 9800X3D still wins over everything. That said, all the AMD CPUs are clumped pretty close together, so I don't see a big deal in obsessing over it. link[www.techpowerup.com]

But nobody plays at 1280x720. Hardly anyone considering a high end CPU plays at 1920x1080. I'm gonna go out on a limb here and say that if you've spend thousands of dollars on your PC, you're probably also playing on a nice monitor.

And as you increase the resolution, the CPU generally becomes less important. So, if you're playing at 2560x1440, just buy what you can afford, and it'll probably perform well.

[Bing Chilling]

how much more is the 9800x3d over the 7800x3d?

also i wouldn't even consider the 9900x3d or 9950x3d unless you do alot of production/synthetic work while also alot of gaming. the 9900x3d and 9950x3d are within margin of error in gaming performance to the 9800x3d but decently better in production.

[Corona Scurrae]

Nobody interested in what his use case is or what GPU he is planning to pair that CPU? Right then

[Bing Chilling]

Originally posted by Yhorm:

Nobody interested in what his use case is or what GPU he is planning to pair that CPU? Right then

i mean, he asked whats the "smartest choice"

imo that means whats the best price to performance.
sure the gpu and use case does matter but buying a high end cpu even with a slightly lacking gpu isn't a bad idea since the GPU is the easiest to replace and having a cpu bottleneck sucks

You can't do much about it with game or application settings without overclocking and that only goes so far.

[Zarginnia]

Originally posted by Yhorm:

Nobody interested in what his use case is or what GPU he is planning to pair that CPU? Right then

9070 XT

[Rumpelcrutchskin]

If you are already going to make the jump from AM4 to AM5 then might as well go for best CPU available and for gaming this is 9800X3D. That way you get maximum worth from your upgrade and it will last longest without another upgrade.

[Dura_Ace]

I am on AM4 and have the 5800x, like you

I could upgrade once more to the 5800X3D but for that price i should get a platform upgrade to AM5 instead, as the cost of the 5800X3D is the same as the newer 9000 chips.

The 5000 and 7000 series had issues with the cache being put on top of the chip. They could not be over clocked due to that. Heat issues. So those chips are locked.

The 9000 series is not locked and the cache is now under the chip.

Since you have the 5800x you are locked into the AM4 dead end platform. IF you want anything better than the 5800x you will need to get the newer AM5 platform.

Add to that all the issues that come with that.

Can your PSU handle the new platform? Cost of new hardware, CPU, Memory, motherboard.

I am ok with staying on AM4.

Show me a game that makes use of more than 8 physical CPU's on the chip. No game made today can make use of the 16 physical CPU's we now see.

[90054321564584560]

all technology will be obsolete after a while. just get the most reasonable one

[tareqalhamrani]

9800X3D