Monday, February 12th 2018
AMD Ryzen "Raven Ridge" Comes with a Limited PCIe Interface
AMD today launched its first desktop Ryzen "Raven Ridge" APUs that combine quad-core "Zen" CPUs with "Vega" based integrated graphics solutions. One of its key specifications that caught our eye is its PCI-Express interface. Apparently, these chips feature just 8 PCI-Express gen 3.0 lanes for discrete graphics, besides 4 lanes dedicated as the chipset-bus, and 4 other lanes driving a 32 Gbps M.2 NVMe slot. What this means for the end-users, is that any discrete graphics cards plugged into the PCI-Express 3.0 x16 slot will run at half the bandwidth - PCI-Express 3.0 x8.
Our various PCI-Express scaling articles, which we regularly redo with the latest high-end GPUs, should tell you that the performance loss between gen 3.0 x16 and gen 3.0 x8 is negligible. This, however, becomes a problem for the small minority of users who combine these processors with AMD X370 chipset motherboards. The second x16 slot (which draws its PCIe lanes by segmenting it from the first x16 slot) won't work, and without at least x8 bandwidth, there's no possibility of NVIDIA SLI functioning, even on X370 motherboards that have SLI certification. One can't even argue that some internal PCIe lane allocation to the iGPU permanently locks 8 lanes away from PEG. AMD confirms that the "Zen" CCX and the "Vega 11" iGPU talk to each other over Infinity Fabric, not PCIe.
AMD responded to our story in advance with this statement:
Our various PCI-Express scaling articles, which we regularly redo with the latest high-end GPUs, should tell you that the performance loss between gen 3.0 x16 and gen 3.0 x8 is negligible. This, however, becomes a problem for the small minority of users who combine these processors with AMD X370 chipset motherboards. The second x16 slot (which draws its PCIe lanes by segmenting it from the first x16 slot) won't work, and without at least x8 bandwidth, there's no possibility of NVIDIA SLI functioning, even on X370 motherboards that have SLI certification. One can't even argue that some internal PCIe lane allocation to the iGPU permanently locks 8 lanes away from PEG. AMD confirms that the "Zen" CCX and the "Vega 11" iGPU talk to each other over Infinity Fabric, not PCIe.
The target market for Raven Ridge, PC builders or DIYers who value the presence of SoC graphics, will select B350 or A320 motherboards, which do not feature the ability to split PCIe lanes. X370 buyers are typically buying the high end Ryzen, such as Ryzen 5 6-core and Ryzen 7 8-core, to go with that class and price motherboard. For the majority of the market, upgrading from the class leading processor graphics inside the Ryzen 5 2400G or Ryzen 3 2200G to a single discrete GPU will be more than enough, given then performance on offer today from discrete graphics cards such as Radeon RX VEGA64 and Radeon RX 580. And today, those buyers can select from our 1st Gen Ryzen desktop processors, including the Ryzen 5 1500X and Ryzen 3 1300X which remain in the product stack for those buyers who value the extra PCIe lanes.
Additionally, we typically expect buyers who want to run mGPU are doing so from day one. These consumers are finding the lure of the of the Threadripper platform very compelling - massive performance, class leading PCIe lanes, and massive memory bandwith are all the perfect complementary features to go with multi-GPU compute, and gaming.
Raven Ridge was created for the ultra thin and light performance notebook segment, but also to scale into the mainstream performance desktop. It does this through the scalability of "Zen" and "Vega" IP, connected by AMDs Infinity Fabric, offering outstanding graphics performance and features for the price point in the desktop market. The scalable nature of the Socket AM4 platform means that there is a path for users to begin with an entry level motherboard and mainstream processor, and now upgrade processor and platform features the same way that people upgrade discrete graphics card.
29 Comments on AMD Ryzen "Raven Ridge" Comes with a Limited PCIe Interface
That said, for many, 8X1 is enough, so...
Sub-par performance at a premium price what a JOKE!
Just get a real Intel system and avoid the headache and wasted time and money! AMD is GARBAGE! I know I have them and they BOTH SUCK! My Q9650 of 9 years of age can not only keep up but is in many tasks faster! OMG I GOT SUCKERED!
I don't think they are even doing crossfire with any card and this APU series... Unless they have a lot end Vega I don't know about.
I get that you had a bad experience, but it sounds like you made some poor calls when buying hardware and should probably have read more reviews before pulling the trigger. Ryzen has made AMD competitive with Intel (still behind, but competitive) for IPC. They're still lagging in pure clock speeds, and their platform has some idiosyncrasies that might hit you badly given your part selection - but that's the nature of not being the de facto industry standard. Ryzen still works amazingly for pretty much everyone who bought it.What you're saying here has absolutely no relation to what you quoted.Kinda-sorta agree, although I doubt there'll be any major differences between them (other than, it seems, X470 being a die shrink or similar redesign for lower power). If I had the money and RAM prices weren't stupid I'd be getting a 2400G + a fast 16GB RAM kit for a HTPC upgrade. I'll hold off for now, though, as it seems the RAM situation might improve somewhat throughout the year.
It's more-so that I've waited since Ryzens release to get at these APUs, so there's a bit of stubbornness in there as well. "Hey AMD, I didn't need a new desktop or workstation, I needed a fresh APU". So I've been biding my time since then... and I'll wait a little longer good measure. Also, I'll probably get a better out-of-box experience, which may be the 400-series best feature.
So yeah, it's ok people are highlighting this.
You then went backwards technologically, to Piledriver, which has known to be shit since forever (part of why Ryzen was made), and you think AMD is the problem?
Confusing.
This is the AMD CPU you should have started with at minimum, to see how technology has advanced:
www.newegg.com/Product/Product.aspx?Item=N82E16819113428&cm_re=Ryzen-_-19-113-428-_-Product
@trickson AMD's Ryzen in anything but sub-par. In fact Ryzen is hitting Intel hard, which can only ever be good for consumers as it drives market competition. And for the record;THAT is why your Ryzen 3 is under-performing. Get another stick of ram for that bad-boy and watch it shine!