Official AMD Ryzen Memory Support
Several sites and fora discussed potential memory limitations on Ryzen in the leaks leading to embargo lift. To some extent, these were true; that said, the internet went a little crazy with its claims on either side of the memory discussion, as it tends to do.
Ryzen officially supports ~2666MHz right now. This is straight from an AMD presentation at last week’s San Francisco event. Ryzen officially supports:
- Dual-channel, dual rank: 1866-2133
- Dual-channel / single rank: 2133-2400
- Single-channel / dual rank: 2400-2667
- Single-channel / single rank: 2667
AMD’s test documents sometimes suggest ~2666MHz speeds for memory during testing to ensure no miscommunication during handshakes with the memory controller, which could damage performance. We have also received suggestions to operate at higher frequencies if they are stable, depending on whom you ask.
We were able to clock up to 2933MHz and used this for most finalized testing. At time of testing, we did not observe performance improvements by moving from 2933MHz to 2666MHz. We were not able to sustain higher clocks than 2933MHz with the Corsair kit that we had access to, and there’s a lack of access to memory subtimings that further complicates higher clocks on DDR4. Now, that said, ASUS got its memory upwards of 3600MHz during the Editor’s Day. This can be done with memory training, presumably a memory kit from an ideal batch and with the right dies, and with fine-tuning of the settings. That includes reference clock modifications. To really get the most out of memory, you’ll have to manually tune reference clock (something we did not want to do for stock benchmarking tests), vDIMM, and then step through memory training, if present. This seems to be easiest on the ASUS Crosshair board that we used for review; in fact, of both boards that we have and in speaking with other editors, the ASUS Crosshair board seemed to offer the most complete feature set at time of early sampling.
To get memory functioning at higher frequencies, given the right motherboard and time, you could:
- Boot at 2400MHz
- Commit EFI change
- Boot at 2666MHz
- Commit EFI change
- Boot at 2933MHz
- Commit EFI change
- Configure vDimm to correct or slightly higher value (e.g. 1.4v)
- Boot to 3200MHz
If you are encountering a subtiming or kit validation issue, it is not possible to fix on the Ryzen platform at this time. No subtimings are accessible. There’s a good chance this stability also relates to memory ICs used, and note that memory vendors are ramping to validate new kits as we speak. Considering how strongly AMD suggested we avoid testing with kits which weren’t the one provided, we’d recommend potential buyers to check the supported CPUs list for memory kits.
Also during time of review, there was only one memory kit officially validated for Ryzen, and it’s the Corsair’s Vengeance LPX 3000MHz kit. Again, AMD and Corsair strongly suggested that we were not use other kits of memory for testing, and so this provided kit is the one used in our benchmarks. You’ll likely see that most other reviewers made the same decision. We were not able to sustain the higher advertised clock-rates of our better memory kits when using the AMD platform.
Ryzen’s Logistical Issues
Ryzen has had some logistical issues. AMD is stretched thin, as are partner samples, and we’re not the only people who’ve tried to get ahold of the team this week. Several manufacturers in the industry have indicated to GN the difficulty of obtaining retail samples for validation and media support, forcing us to get a little creative in our usual pings for sanity checks. Zen is a big push for AMD, and it was sprung on everyone with little notice; sure, we all knew it was coming, but the preparation period between final announcement and launch has been in the span of weeks to a month. AMD told GN in a last-minute phone discussion that most board vendors have had 3 weeks (from March 2) to finalize EFI, and noted that some motherboards still “need more time in the oven.” This should explain some of the initial bugs in EFI from multiple vendors. Note carefully that EFI version can heavily impact performance in some cases. GN used the latest (correct) ASUS EFI version, detailed on the next page, but other board vendors shipped updates late into the review week. Disparity in review performance can be partially attributed to motherboard support and EFI revision.
Board vendors aren’t the only ones who have had that limited window. That’s counting memory, cooling, and board partners alike.
Of all the architectures we’ve reviewed these past few years, Zen is the first one where we were receiving pings from manufacturing partners and system integrators to assist in sanity checks (third-party/peer data validation). Of course, we also sent several of these sanity check / validation requests to those same SIs and board partners (and have a 50-email long thread with AMD), along with several of our peers in the media space. Motherboard vendors have had limited time on EFI development, leaving most of the BIOS interfaces a little Spartan, and with at least one EFI update per vendor in the past week.
Cooling will be limited on day one, but should rapidly expand options. If you’re unhappy with the current selection of coolers, give it some time. Most of the brackets are on boats from China right now, or soon will be. Generally, any of the cooling manufacturers operating factories in China (due to long lead times) will be late to launch as a result of the scramble. Companies like Noctua and Alphacool, both of whom operate manufacturing outside of China, were able to get brackets or adapters turned around with a shorter lead time. That said, there are still other challenges.
In speaking with several cooling manufacturers, we’ve learned that AMD’s provided specification for cooler retention brackets is allegedly inadequate for usage by some cooler makers. This primarily affects makers of liquid coolers, which – by nature of their size and reduced sag – require less force than an air cooler might. According to the spec, from the information we’ve gathered, AMD is recommending 60-90lbft of force to secure an air cooler. There is allegedly no specification provided for smaller coolers, and so CLC makers are left taking their best guess at mounting force. The 60-90lbft number could result in excessive force, a problem for coolers which are not supported top-down on the pump head.
In speaking with these companies, it sounds like the delay on affected CLCs and AIOs will extend into mid-March. The manufacturers are planning AM4 brackets for existing product lines once they have been produced and shipped to channels.
Asked for comment, AMD stated:
“There are no specific guidelines for LCS/CLC – we do not differentiate between cooler types, but specify the minimum clamping force to ensure that during shipping or other transportation events that the CPU is held securely in the socket and maintain good contact.”
This said, some motherboards (like the ASUS Crosshair) support both AM3 and AM4 mounting holes. For these, you’ll need to separately grab an AM3 backplate, replace the AM4 backplate, and then mount your cooler normally. That is, assuming it’s one which doesn’t use a custom backplate (and those should still align with AM3 holes).
Where are the Mini-ITX Boards? (& EFI)
Board partner challenges were not limited to a small time window on EFI development. If you’re wondering where all the mini-ITX AM4 motherboards are, e.g. those with X300 chipsets, the answer is that most are still in design and development. Mini-ITX motherboards using the shrunken down AM4 chipsets have an extra layer of complexity – literally, generally needing an extra PCB layer – and that takes time to build. We’ve spoken with a few manufacturers and know that boards are on the way, they just might not all be here for launch.
For this launch, keep in mind that EFI version and motherboard will have an impact on performance in potentially large ways. Even smaller methodological things that we account for, like running Windows in “Performance” power mode rather than “Balanced,” can have sometimes noteworthy impact on performance. In this particular instance, it’s because of core parking.
Regardless, we’re trending into methodology discussion.