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You say that, but DDR6 will double the memory bandwidth over DDR5. This means modern systems will go beyond 200GB/s memory bandwidth just for the CPU alone.
by imtringued 11mo ago
You say that, but DDR6 will double the memory bandwidth over DDR5. This means modern systems will go beyond 200GB/s memory bandwidth just for the CPU alone.
- 0cf8612b2e1e 11mo agoAnd? What real world impact will that have for people typing up an email and browsing the web?
- glitchc 11mo agoIt majes a huge difference for local AI models.
- kvemkon 11mo ago> DDR6 will double the memory bandwidth over DDR5 Considering PC desktops. DDR4 is 3200 MT/s max JEDEC. DDR5 is available on AMD since 3 years and is 5600. DDR6 specification is almost finished. It looks like DDR5 will double performance just right before new DDR6 DIMMs appear. Thus I'd expect DDR6 to double the bandwidth just as late when the new memory standard arrives.
- yetihehe 11mo ago> DDR5 is available on AMD since 3 years and is 5600 Strange, I bought 64GB DDR5 6400MHz last year and apparently my motherboard can handle up to 7200MHz (or more with overclocking).
- kvemkon 11mo agoThough clarified at the start about Desktop, but missed JEDEC applying, of course, generally for the whole post.
- wtallis 11mo agoAMD's CPUs don't support more than 5600 MT/s without overclocking; they're still using the same IO die from Zen 4, so their memory controller is pretty outdated. Zen 6 should introduce a new IO die with a better memory controller, but for now 6000 MT/s is the fastest reasonable memory overclock for AMD desktops. Intel's desktop CPUs from last year support up to 5600 MT/s with regular DDR5 DIMMs, or 6400 MT/s for CUDIMMs. Speeds higher than this are achievable, but are overclocking. If your memory modules are rated for 6400 MT/s, they are most likely advertising the speed when using an Intel XMP or AMD EXPO profile to overclock the memory (and the CPU's memory controller). The JEDEC standard profile likely is no faster than 5600 MT/s. It's also possible that you bought last year a kit of CUDIMMs rated for 6400 MT/s without overclocking, brand new to the market at that time, and of no help whatsoever with any CPU that isn't an Intel Arrow Lake.
- yetihehe 10mo agoNow that you say that, I checked in bios and looks like you're right. I have 4 sticks of "DDR5-4800-16GB @6400MHz". It was probably marketing speed, but works stable and memtest didn't find any errors.
- nopesayer 10mo agoCute but that's not how it works. The singaling is double the transfers but the bandwidth does not double. We've seen what ... 5 ... itterations now and people still get this wrong. The doubling of transfers comes at the cost of latency and processing overhead, always, until the new standard matures and might match the predecessor latency. Did dual channel DDR5 double dual channel DDR4 bandwidth? Short answer ... nope, not even close, and DDR4 4000 remains viable and trades blows with DDR5 to this day in application performance despite "losing" in sulunthetics.