AMD Zen 4 Ryzen 9 7950X and Ryzen 5 7600X Review: Retaking The High-End
by Ryan Smith & Gavin Bonshor on September 26, 2022 9:00 AM ESTMore I/O For AM5: PCIe 5, Additional PCIe Lanes, & More Displays
AMD’s other big expenditure using socket AM5’s additional pins is on I/O support. While AM4 already supported a fair bit of I/O, including 24 PCIe lanes, 3 displays, and 4 Superspeed USB ports, there was still room for improvement. So for AM5, AMD has increased the amount of I/O and the flexibility offered with the platform.
The biggest change here is that the AM5 socket now provides for 28 lanes of PCIe, a net gain of 4 lanes. More significantly still, PCIe 5.0 is now supported (at least on the Ryzen 7000 “Raphael” processors), doubling the bandwidth of all of those PCIe lanes to a max of 4GB/sec/lane. Which gives the chip a maximum cumulative PCIe bandwidth of 112GB/sec in each direction.
In practice, those additional lanes are intended for NVMe drives, giving AM5 a second x4 connection to drive a second NVMe drive; though we have seen some motherboard designs where vendors are stealing the second x4 for a PCIe 5.0 x4 slot. Past that, things look a lot like AM4, with 16 PCIe lanes to directly drive one or more PCIe slots, and then 4 lanes for hooking up the chipset.
Meanwhile, the updated socket also offers enough pins for the CPU to drive 4 Superspeed USB 3.x ports, and a USB 2 port. The USB 2 port is new for this generation, and meanwhile 3 of those USB 3 ports now also support the USB Type-C connector, unlike AM4 which could only natively drive Type-A ports. As a result, AM5 CPUs can drive a total of 3 Superspeed Type-C ports, a fourth Superspeed Type-A port, and then the aforementioned USB 2 port.
There has been one regression, however, and that is SATA support. Whereas AM4 CPUs could drive a mix of NVMe and SATA drives (up to 2 SATA + a PCIe x2 for NVMe), AM5 is purely PCIe. So there is no native SATA support on the CPU, and supplying that will come from the chipset.
To visualize this, we’ll use part of the AM5 chipset diagram. We’ll go more into the specifics of the chipsets in a bit, but lays out what is wired to the CPU, and what will need to be wired to the chipset. Of note there, the current chipsets only use PCIe 4.0 connectivity to the Ryzen CPU, so the current generation of chipsets will not be making full use of the bandwidth capabilities of the CPU itself.
Which with the addition of PCIe 5.0 support to the platform, is going to be a recurring theme. While AMD has baked in 5.0 support into the Raphael CPUs, it’s up to motherboard vendors to actually make it so. Compared to PCIe 4.0, 5.0 has much tighter signal integrity requirements (the signaling frequency has been doubled), which at least at this time, makes PCIe 5.0 expensive to implement. A very well-designed motherboard is required with impeccable traces, and on top of that the overall short throw of PCIe 5.0 means that retimers/redrivers become necessary rather quickly. So while AM5 can support PCIe 5.0 throughout, the reality is that we’re still going to see a lot of PCIe 4.0 in use even in higher-end motherboards.
As for the necessity of PCIe 5.0 overall, thus far AMD is primarily focused on what it means for NVMe drive speeds. The first generation of PCIe 5.0-enabled consumer SSDs are expected to land a bit later this year, and they should be able to hit sequential burst transfer rates above the limits of PCIe 4.0 (~7GB/sec).
Past that, NVIDIA’s newly announced Ada Lovelace architecture GeForce RTX 40 series video cards do not support PCIe 5.0. So while we’re awaiting AMD to announce their RDNA 3-based product lineup later this year, regardless of what AMD does, the bulk of video cards sold next year are not going to use PCIe 5.0. So there is a bit less pressure on motherboard manufactures (and motherboard buyers) to get boards that support PCIe 5.0 to anything beyond a couple of M.2 slots.
Finally, in conjunction with the USB I/O changes, AM5 also introduces some display I/O changes. Whereas AM4 could directly drive up to 3 displays, AM5 brings this to 4. Specifically, AM5 offers one dedicated display output (which will generally be allocated to HDMI), while the other 3 display outputs are available over those 3 USB Type-C ports as DisplayPort alt mode. It’ll be up to motherboard manufacturers if they want to expose any of these USB-C root ports as physical USB-C ports or as DisplayPorts, but so far from the motherboard designs we’ve seen, the former is more common (though certainly not universal).
Anticipating a shift to more USB Type-C displays, AMD is also implementing what they call “hybrid graphics” support on AM5. Unlike previous products where this referred to linking up the integrated graphics with a discrete GPU in CrossFire mode, this time around it refers to being able to being able to use the mobo/iGPU’s display outputs to drive a monitor while using a dGPU to render content. This is largely lifted from AMD’s laptop technologies, where similar techniques are used to allow the dGPU to be powered down when it’s not in use. In the case of desktop processors, this just means every display output will work, regardless of whether it’s plugged into ports coming from the CPU or a discrete video card.
It’s also worth noting that AM5 is bringing a few other, more minor updates to other comms protocols. Among these is support for MIPI’s (relatively) new I3C chip-to-chip signaling standard, which will ultimately be supplanting the long-used I2C standard. As well, AM5 doubles the number of I2C/I3C ports available, bringing the total to 4 ports. The platform also adds a second (enhanced) Serial Peripheral Interface (eSPI/SPI) port, and on the audio front, adds support for the Digital Mic and MIPI’s Soundwire standard for low-cost audio peripherals.
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Silver5urfer - Tuesday, September 27, 2022 - link
Intel won't sell new mobos. They already have Z690 saturation. Barely anyone will get Z790. AMD on the other hand will continue to sell new boards, the quarter is not based on the Client only. It will include the HPC. Intel lost money there, and AMD won't be losing because Genoa is on track and SPR XEON is delayed.AMD AM5 is not just hey this thing is fast and just for gaming. It will be a socket that is going to last until Intel Nova Lake launches that is next 2 Intel sockets. That is a huge advantage for a small price for paying customers now.
Also why is everyone chanting same BS that GN Steve did with AMD boards are too expensive, did you see how Z690 was at when it launched same thing it was expensive ? And DDR4 boards are worse quality and features than the premium cut DDR5. Then Intel launched B660 and AMD's B650/E is also coming. So nope that BS argument about Mobo pricing is too much thrown around. Once the B650 launches by that time 13th gen will hit Retail market and new GPUs as well. And it's November season and in America the Black Friday sales will kick in and see price cut for all products we are seeing now.
So ultimately AMD is not going to lose money.
The biggest BS from a smart customer pov is with Intel LGA1700 EOL and the whole socket bending crap, it's like AM4's unreliable IMC and poor IODie with it's issues. AM5 needs to prove itself but given how they removed the IF from memory clocks I can bet it won't have the issues from AM4.
X3D is a niche market it won't be chart topper for sales at-least if it's again 7800X3D single SKU. Same for KS bin. It depends on how AMD will execute, idk why every single AMD fan says X3D is going to do something if AMD can clock it this high and also allow tuning then it will be a true gen refresh to compete vs Meteor Lake else it will be just a Gaming Juggernaut. Reply
nandnandnand - Tuesday, September 27, 2022 - link
@Silver5urfer rumored to be 3 SKUs, including a 7900X3D, and +30% average performance instead of 15%. I guess that would be a result of improved latency, bandwidth, no voltage/clock decreases, etc. ReplySilver5urfer - Wednesday, September 28, 2022 - link
A 7950X3D means it will have extreme high heat because not only single cache stack you are adding 2 stacks atop the CCDs, how will AMD able to remove that ? Unless the way Cowos TSMC Stacking is technically changed OR they have to lap out the IHS internally to reduce the thickness and compensate the high heat transfer. The current IHS is thick due to many reasons one can assume - The LGA1718 stability, Chiplet integrity with high heat and pressure of HS and cooler compat and it causes the heat density increase, which is why 95C.I really think a 7800X3D is the only way for AMD even though rumors mention 3SKUs because a total SKU refresh totally cannibalize the entire 7000 lineup, because a 7600X is to get best gaming out of AM5 with cheaper option almost at more than 1/2 the price reduction vs a top end R9. And R7 7900X is basically an all rounder like 5900X best for gaming and production now you add the Cache block it would have to fight with 7900X.
Voltage reduction was done on Zen 3 because AMD shoved 1.4v through all Ryzen 5000 processors, insanely high and IODie was also on high voltage, causing all that instability add the 1.3v bin silicon, everything gets better including the heat density. Zen 4 TSMC 5N is much better because it's just 1.2v now at high clock rate. The voltage is not an issue anymore, the design of the Zen 4 itself is like this, how AMD intended to breathe fire at 95C even for 7600X is the hint. Reply
nandnandnand - Wednesday, September 28, 2022 - link
Heat was never the problem for the 5800X3D. It was only voltage, due to using an immature 3D (2.5D) chiplet technology that could not be run at the higher voltages. So I don't think the 7950X3D can't happen. If they have to drop voltages and clocks again, then hopefully the cache has improved.I think AMD should do at least a 7950X3D and 7800X3D. They can prevent cannibalization by giving it a healthy price bump. Probably +$100 to the 7950X3D, +$50 to the 7800X3D, and let the 7700X price drift lower. 7900X3D doesn't make sense, and people would love a 7600X3D but AMD would not. Reply
nandnandnand - Tuesday, September 27, 2022 - link
@Hifihedgehog OP compared 7000X3D to the 13900KS, that's what I addressed. ReplyHifihedgehog - Tuesday, September 27, 2022 - link
Wrong: the i9-13900K is less than $600. The 7950X is going to have to have its price lowered, especially with the price of DDR5 and the motherboards simply off the charts. And good too: Lisa Su needs to be running a price war and not pretend that her company has more market share. ReplyThe Von Matrices - Tuesday, September 27, 2022 - link
A price war doesn't benefit AMD when they are supply constrained by TSMC and selling every chip they can manufacture. There's a reason that AMD doesn't offer any products in the <=$100 CPU market right now and it isn't because they don't want to make money. ReplyHifihedgehog - Tuesday, September 27, 2022 - link
https://download.intel.com/newsroom/2022/2022innov... Replydwade123 - Tuesday, September 27, 2022 - link
Overheated and overpriced. Don't let those scumbags tell you that "95C is normal" because it's not. Avoid at all cost! ReplyThanny - Tuesday, September 27, 2022 - link
Running the memory at JEDEC speeds is definitely the wrong choice for a review. While it may be true that most people don't set the memory profile in the BIOS, none of those people read CPU reviews. Essentially every person who would read this reviews will be setting memory to the XMP/EXPO settings.So you're essentially invalidating your test results for the only people who see them. Reply