Nick Evanson, Hardware writer
This month I’m testing: Actually not much! Asus’ cable-hiding technology and one of Gigabyte’s newest laptops, but mostly I was testing a new display panel colorimeter. It’s surprising how much your eyes can deceive you when looking at a monitor.
PCI Express has been the standard system for sending data and instructions around a computer for two decades. The specification of how everything works has gone through regular updates, each offering twice the performance of the previous one. PCIe 5.0 was released almost four years ago and is now the newest version you can find in any gaming PC. It’s also nearly worthless thanks to the disappointing hardware that supports it.
For a computer to support PCIe 5.0, it needs one of two things, preferably both. The first of these is the CPU; The latest generation processors from AMD and Intel all have PCIe 5.0 controllers onboard. Ryzen 7000 series chips feature 28 Gen 5 PCIe lanes, with the first 16 reserved for the graphics card slot, eight reserved for M.2 NVMe slots, and the remaining four used to communicate with the motherboard chipset. (more on this confusing mess in a moment).
Intel’s 14th Gen Core processors have the same number of lanes as AMD, but they’re all split quite differently. Only sixteen of these are PCIe 5.0 and the rest are the slower 4.0 specification; however, eight lanes are used for the motherboard chipset, allowing a single SSD to be connected directly to the CPU. Not really, because the 16th Gen 5 line can be switched to 8+8 mode, half for the graphics card and half for the SSDs (AMD chips can do this too).
Still, on paper, AMD completely outperforms Intel when it comes to PCIe 5.0 support. But things get more complicated with Ryzen processors because to access the full 5th Gen line, you need a motherboard that uses the E versions of the latest chipsets. For example, an X670 motherboard has a PCIe 4.0 graphics card slot and no more than a single PCIe 5.0 SSD slot. When you move to the X670E motherboard, the GPU slot becomes 5.0 and there may be two Gen 5 M.2 slots (but usually only one).
If this is a bit confusing, I can assure you that this is a better situation than Intel’s current PCIe 5.0 support. Take the ASRock Z790 Nova motherboard as an example. It’s a nice motherboard, well designed, and has a total of six M.2 SSDs. Two of them are connected directly to the CPU for best performance, and the one closest to the processor supports PCIe 5.0 SSD. Unfortunately, if you put any When you insert the SSD into this slot, the CPU automatically switches the graphics card slot to eight lanes (aka PCIe x8).
While this still leaves the other eight Gen 5 lanes available, they can’t be split any further, and since M.2 slots always use four lanes, you’re wasting four PCIe 5.0 lanes by using the first SSD slot. Even if you use Gen 4 or even Gen 3 SSD. Not all Intel motherboards do this, but those that use the Z790 chipset and have a Gen 5 SSD slot will have this limitation.
But it’s not just SSD slots that Intel messed up. The bandwidth of a single PCIe 5.0 lane is just under 4 GB/s, so eight of them add up to 31.5 GB/s (let’s just call it 32). This is the same as the 16-lane in the Gen 4, so in theory, placing a Gen 5 graphics card in an eight-lane slot should be no problem.
But there are no 5th Generation graphics cards; they all still use PCIe 4.0 at best. The next round of new GPUs from AMD, Intel, and Nvidia may move to the newer spec, but given that they’ve just moved to Gen 4 on their latest generation cards, there’s a good chance they won’t.
So, if you’re like me and have the ASRock Z790 motherboard, no matter which GPU you use, if you install an SSD in the first M.2 slot, the card will be forced to run in PCIe 4.0 x8 mode (same as Gen 3 x16). Fortunately, no game comes close to maximizing the bandwidth of a PCI Express graphics card connection, but who’s to say it won’t happen soon?
All these disappointments could be forgiven if PCIe 5.0 SSDs were great and worth buying. The sad part is that these are a waste of money. Of course, peak performance in synthetic tests makes the older Gen 4 drives seem pretty slow by comparison, but in real use you’ll barely notice the difference.
This may seem odd, given that one of the few PCIe 5.0 SSDs worth considering has a top sequential read/write speed well over 10,000 MB/s; a basic Gen 4 drive would be only half that rate. That’s because games, apps, and even entire operating systems are designed to move small amounts of data only when needed, because most computers don’t have very fast storage. Gen 5 SSDs can only show their true limits in very specific scenarios; very few of these have been experienced in gaming or general computing.
Then there’s price and heat, which adds salt to the wound. Go to products like Newegg and look at how much an original Gen 5 SSD costs, that is, ones that use the full performance of the connection. You’re looking at $150 or more for a 1TB PCIe 5.0 SSD, and for that amount of money you can get one of the best 2TB Gen 4 drives and still get change.
Does Gen 5 really have early adoption issues, or is it just a case of vendors not interested in supporting it properly?
All 5th Gen SSDs run hotter than 4th Gen SSDs, and it’s not just a few degrees. You have Using a good cooling system, whether it’s a dedicated heatsink and fan to absorb and dissipate heat, or a large metal heatsink on the motherboard. In the first case, this is an additional cost to consider and depending on the size of your graphics card you may not have room for it.
One could argue that this is just a case of ‘early adopter’ issues and that things will get much better as technology advances. While this is certainly true, it’s worth noting that the PCIe 5.0 specification was released almost four years ago, with AMD’s Ryzen 7000 series launching in the second half of 2022. So does Gen 5 really have early adoption issues, or is it just a case of Vendors not interested in properly supporting them all?
It’s a little bit of both, to be honest. Each successive revision of PCI Express doubles the amount of bandwidth each lane has, and until version 5.0 this was achieved by running the bus clocks twice as fast. Try doubling your CPU or GPU clocks and see what happens. Okay, so it’s not the same thing, but dramatically increasing clock speeds is no easy task, even with a relatively simple system like PCI Express. Electrical tolerances need to be extremely tight, which increases the complexity and cost of everything.
This is especially true for SSDs. To be fully PCIe 5.0 compatible, the controller chip needs to run faster than the 4th Gen chip, and the NAND flash memory chips also need to read and write data at a much higher speed. Very few companies currently have chips that can do all this and unfortunately generate a lot of heat. Market for Gen 5 SSDs more Smaller than 4th Generation drives; Therefore, lower demand means higher relative costs.
However, AMD and Intel haven’t done their best in implementing PCIe 5.0; In the first case, the 5th Gen graphics card slot is wasted because no one is selling the 5th Gen card. The intentional chipset limitation between E and non-E motherboards adds confusion to the whole thing. Also, this is completely unnecessary as there are no physical differences between the chips used in, for example, B650 and B650E motherboards.
It’s clear that Intel isn’t very interested in 5th Gen PCIe; Implementing it on 14th Gen desktop CPUs and a 700 series chipset amounts to one PCIe 5.0 x16 slot, a maximum of one 5th Gen M.2 slot, and a whole lot of cards. pesky configuration restrictions. Intel doesn’t seem to offer anything much better with Arrow Lake, either.
PCIe 5.0 is virtually useless right now, or at least less used, if that makes sense. Support doesn’t look good in the near future either, but luckily for us Gen 4 is more than good. This technology is now seven years old, but we’re still far from the point where this will be a limitation in gaming. At some point every desktop will be fully Gen 5 from top to bottom, but given the speed at which PCI Express is being implemented we won’t have to worry about that for long.
Let’s hope we don’t experience the same problems again with the 7th Gen or similar!